The Posterous iPhone app has been updated to incorporate spaces, but the announcement doesn't mention the Android app. Posterous has also improved ways of finding and following spaces, adding a 'Popular' tab for real-time highlights from around Posterous and an 'Activity' tab showing likes, comments, follows and such from your spaces and those you follow.

Posterous Reborn

We used to think of Posterous as a light blogging service, and it wasn't clear how it distinguished itself from its competitors. Sure, it had nifty little features like custom domains and built-in Markdown support, but these weren't features for everyday users. Tumblr, the clearest competitor, began to leave Posterous in the dust. But after today's left turn, it's not even clear Posterous and Tumblr are in the same game anymore.

So, why share to your social circles using Posterous instead of Facebook or Google Plus? Well, does Facebook or Plus let you choose your own theme for each friend list or circle? Posterous does. Can each Facebook friend list or Google Plus circle have its own custom Web address? Not without more trouble than it's worth. Posterous has issued a challenge to the "silo" model. It lets you share the right stuff with the right people in the way that suits you best.

Posterous Users, Rest Assured

In the announcement, the change is described as a "brand new service for the Web, iPhone and Android that replaces the current service." That sounds drastic, and existing users could be forgiven for feeling a bit unnerved, but as it turns out, existing Posterous sites will survive the transition to Spaces just fine.

Clearly, while we've all been watching all the big Tumblr and WordPress news, the Posterous team has been busy in the kitchen.

What Exactly Is Blogging, Anyway?

WordPress and Tumblr are showing great usage numbers, and maybe that's why their competitors are moving to distinguish themselves. Blogger, Google's popular blogging platform, may be rolled into Google Plus in some way, and Google's social network is itself a fairly compelling publishing platform for medium-length posts. New startups like Jux are taking what might be called a "maximalist" approach to blogging, turning it into a bombastic, full-screen experience. Posterous, for its part, seems to be hanging onto its focus on simplicity and usability.

Which publishing tools do you like best? Let's discuss in the comments.

This time last year, we compared the growth of the two leading light blogging services: Tumblr and Posterous. The conclusion was that Tumblr had all but defeated its rival. All through 2010, Tumblr showed exponential growth. That has continued into 2011. Over the past year, Tumblr has grown from just over 100 million visits per month to over 300 million now (according to Quantcast). Over the same period, Posterous has grown from about 7M visits per month to about 11M. So the gap has widened: a year ago Tumblr got 14-15 times more visits per month, now it's double that.

Tumblr is now so popular that its founder got invited to The White House and its logo acquired a fish jumping through it. Tumblr is also getting 12 billion page views per month, an estimated 8 times more than Wordpress.com.

A better comparison these days is between Tumblr and Wordpress.com, the leading full blogging platform. While Wordpress.com still gets more visits (but not page views, as we'll see below), Tumblr is drawing ever closer.

Tumblr vs. Wordpress.com, in visits per month.

The two services offer different things, so this is somewhat of an apples and oranges comparison. Wordpress.com is a fully-fledged hosted blogging platform, while Tumblr is a light blogging and curation service. I myself use both products. However, both are blogging services and so it's worth comparing the statistics.

At the end of last year we estimated that Wordpress.com was larger than Tumblr in terms of unique visitors and number of bloggers. However we noted that Tumblr had about twice the number of page views per month.

On the page view front at least, Tumblr has exploded in recent months. Quantcast puts it at 12 billion per month currently, compared to 1.4B for Wordpress.com. So Tumblr now gets 8.5 times more page views per month than Wordpress.com (at least according to Quantcast, which in my experience tends to be the most accurate public web statistics tool).

Before we get too excited, we should remember that Facebook is still a blue whale compared to both Tumblr and Wordpress.com. Quantcast has Facebook at 7.4 billion visits per month in the U.S. alone.

What's the upshot of all this? Maybe just that Tumblr has scaled incredibly well and shows no signs of slowing down. Wordpress.com hasn't had the same exponential growth, but it's certainly been no slouch either. Both services are enormously popular and many people use them side by side.

Let us know your thoughts on Tumblr compared to Wordpress.com in the comments. Should Wordpress.com be worried?

Whenever I'm checking my email, one of two things can happen. I get an email, click on a link, and 20 minutes later I'm not sure how I ended up on Facebook but yes, I would love to attend a dinner party next Thursday. If I'm truly task-focused, however, I'll at the very least end up with a screen full of so many new tabs that I forget which tab I'm on in the first place. Either way, email can set me off on a confusing and messy adventure and Microsoft has an answer I'd love to see become a standard.

Today at the Web 2.0 Expo in San Francisco, Microsoft is announcing a new type of interactive email that keeps you focused on getting through your email while still being able to look at pictures, watch videos, accept friend requests and more.

Last December, the company started helping users with these sorts of emails with something called Active Views. Active Views would take links in your inbox and turn them into embedded content. That way the YouTube link your friend sent isn't just a jumbled collection of characters, it's that video of the cat falling of the table. Or whatever. Whatever the video, you could experience it directly from within your email, rather than opening a new browser tab.

Since December, Microsoft says Hotmail has served up more than 1 billion links in this fashion. That number is about to grow drastically.

The company is announcing a round of new partnerships today. Within these emails, users will be able to immediately respond to connection requests on LinkedIn, add movies to their queue on Netflix, see deals that are active when they open their email rather than old expired ones on LivingSocial and even comment directly on posts sent to them from Posterous.

The feature works by allowing partner companies send emails with embedded JavaScript functionality, which Hotmail then runs in a fully sandboxed (and therefor secure) environment. Currently, the feature only works on the webmail version of Hotmail, not on mobile or in an email client, but external functionality could come in the future. Will we see this become a standard that's used across email clients? Mehta says that, "the notion is that this will move to a standard at some point. We don't generally throw out a standard and see if people will come."

We asked if we would see Facebook added to this list in the near future and while Mehta said Microsoft didn't have anything to announce on that front at this time, we expect that those Facebook friend requests and event invites aren't far off. After all, 16% of all email in Hotmail is a Facebook notification of some sort.

Garry Tan has announced that he is leaving Posterous, the ultra-simplistic microblogging company he helped found in 2008. Tan wrote on his blog today that it was time to move on and that he would be taking an advisory role with the company in order to do what he was most passionate about - work with startups.

"My greatest passions lie with the early stage of building world-changing consumer products," writes Tan. "To that end, I've decided to join the team at Y Combinator as a designer-in-residence and help the dozens of top pre-seed startups in the newest Winter 2011 batch reach their potential through excellent user experience."

Our own Audrey Watters calls the move "huge for YCombinator", relating how she watched Tan conduct back-to-back mentoring sessions for hours on end at a recent startup event.

Rafael Corrales, CEO of the Silicon Valley VC-backed startup LearnBoost, agrees that the move is a big one.

"It's amazing how Y Combinator has recently recruited some of the best guys in the Valley," said Corrales. "It's like a miniature version of what Facebook has done the past few years."

Posterous itself was a YCombinator-funded startup, so Tan will be returning to his roots in some ways. Tan writes that he feels comfortable that Posterous will be in good hands:

Just as Posterous has prospered, grown and changed, so to is it time for me to evolve my role. Effective today, I'm ending my day-to-day development with Posterous and moving into an advisory role. Though my day-to-day may change, my faith in the team and the product is unchanged and unwavering. Posterous is in good hands and on the right track to fulfilling its potential. I am proud of what we've built together and look forward to the future with anticipation to see where the team and you, the users, take this very special community. [...] I am greatly thankful to our team, investors and most of all our users for all the amazing work and adventures. Thanks for all of your support.

Good luck Garry!

This year there was plenty of competition. Foursquare won the battle of the check-in apps, Flipboard created an innovative iPad app that caught our imagination, Instagram burst onto the scene with a mobile photo app. The LittleCo that impressed us the most though was New York-based Tumblr.

Tumblr launched back in 2007, but this year it really took off in terms of growth - crushing its nearest light blogging rival, Posterous. Tumblr achieved this growth at surprisingly low staffing levels: just 16 employees, with an estimated 20 before end of 2010. It's got plenty of money behind it, though. The company has raised $40m. $30m of that was raised this month from existing investors Spark Capital and Union Square Ventures, plus new investors Sequoia Capital (who backed Google in 1999, before it went big).

Tumblr currently boasts over 11 million blogs running on its service, perhaps leading to some performance hiccups recently.

In a recent comparison we did between Tumblr and the popular blogging service Wordpress, we discovered that people who visit Tumblr blogs view far more pages per person and twice as many pages in total. WordPress still has many more publishers and far more site visitors, but Tumblr is doing better on a user engagement level.

Heading into 2011, Tumblr has a full tank of funding petrol and is racing full speed up the page view growth slope. Content curation is expected to be a big trend of 2011, so next year could be another tipping point again for this trendy New York startup.

What do you think of our choice for Best LittleCo of 2010? Do you agree with Tumblr, or should it have been another startup? As always, let us know in the comments.

We spoke with Posterous co-founder and CEO Sachin Agarwal yesterday and he told us that the new feature is an "email list on steroids" and that it's "the last email list you'll ever need."

In moving beyond its origins as a "minimalist blogging platform", you see, Posterous is working to become a minimalist, email-based group-blogging platform that makes everything about communicating with multiple people by email as simple as possible. Creating one of these group email lists, or group blogs, is as simple as sending an email to Posterous.

As you can see in the image, the subject will be the name of the blog and the body, a list of emails, are all of the members. Only the group's creator needs to be a Posterous member and, if they're not at the time of its creation, they will have an account created right then. The end result is a blog, which can be set to either public or private, to which any of its members may contribute by email or by using the website. Agarwal offered a number of use cases, from events to clubs to blogging group travels.

The interesting part here is that the feature is a cyborg, of sorts - it's part blog, part email list. As you can see, Posterous has taken a big bite off of Twitter's recent redesign, using a two-pane view with timeline along the left with an expanded view along the right. For those that don't want or don't care about the Web-based blog portion, the entire thing exists as an email interaction. Every update sends an email to all members and members can reply by email. Any inline media, such as videos, pictures, or even links to videos, are automatically resized and embedded, meaning even the most tech un-savvy can participate.

The feature has been in beta for the past week with about a thousand users testing it and it is going live today. The group feature comes as a bit of a surprise, as when we first heard Posterous would be introducing a "group blogging" feature, email lists never even came to mind. But with its foundation in email-based posting, the feature does seem to make sense.

"We've always been known as a platform that can post by email very easily, but we've also been about consumption by email," said Agarwal. "Our goal has always been to help normal people share."

If it didn't offer this sort of "bridging-the-gap" functionality, we would have to ask what this does that something like Facebook doesn't, but an email list that just happens to be a blog, and vice versa, is something we could see gaining traction among groups that might not otherwise see eye-to-eye on how to communicate with each other online. It brings the email diehards together with the blogging, text messaging, Facebook-aholics.

In some ways, it seems like an out of the blue move for the once minimalist blogging platform. In others, it seems like the natural progression.

Tumblr and similar services are sometimes termed light blogging, as they enable people to publish 'found' things very quickly and at the click of a button. Tumblr is the market leader amongst such tools, followed by Posterous, Soup.io, Noovo and others. Tumblr has grown the most in recent times, but Posterous has fought hard. Let's review the fast-moving and often entertaining moves in this market over 2010.

Tumblr has always been a step ahead, as it launched back in April 2007 whereas Posterous didn't launch until June 2008. In December last year, Tumblr announced a couple of innovations that kick-started 2010: real-time alerts and enabling Twitter clients to support Tumblr.

Posterous Gets Aggressive, Takes on Tumblr & Others

Tumblr may have gotten off to a better start in 2010, but Posterous soon upped the ante with new features.

In April, Posterous announced that it was shedding its minimalist origins and essentially began competing on feature set with Tumblr. When it launched, the only way to post a story to Posterous was by email. However in April 2010, Posterous added a full rich text editor and put more emphasis on sharing media files. It also hooked into Facebook's OpenGraph API and added 'like' buttons.

In June, Posterous embarked on an aggressive marketing push to get Tumblr's users to switch. It started promoting tools that enabled users to import their content from other products - including from Tumblr. The campaign infamously called out a number of blogging products as "dying platforms." It was a brazen move by Posterous and entertaining to watch, but ultimately it didn't succeed. In the final analysis, Tumblr grew the most in 2010.

The main factors in Tumblr's growth over 2010 have been its first mover advantage, celebrities and big media companies using Tumblr sites, and Tumblr's ability to socialize its service better than Posterous.

Traditional Media Companies Flock to Tumblr

A good example of big media flocking to these tools (but mostly Tumblr) in 2010 was National Public Radio (NPR). ReadWriteWeb's Chris Cameron spoke to NPR senior strategist Andy Carvin in September to find out how the organization was leveraging Tumblr.

"Part of what we do is experiment on different platforms, and it seemed apparent to us that there was a sizable number of NPR fans on Tumblr," Carvin told us. "It's less about page views and more about engaging a community that enjoys NPR."

Carvin explained that NPR is taking a very experimental approach to Tumblr in terms of curating content to share, engaging one-on-one with followers and determining how to voice the blog.

A number of traditional media outlets began to use Tumblr this year, including Newsweek, Life Magazine and Rolling Stone.

Finally, we should also mention that many full blogging platforms added Tumblr and Posterous-like functionality in 2010. For example, in September leading blog platform Wordpress.com added subscriptions - reminding our writer Mike Melanson of Tumblr's "Follow" feature.

Poll: Which Light Blogging Tool Do You Use?

Overall, it was a great year for Tumblr in terms of its user growth and uptake from traditional media companies. We commend Posterous too for its excellent features and brave marketing moves (many of the ReadWriteWeb team use Posterous - although personally I use one of the underdogs, Soup.io).

2010 was a year in which light blogging tools showed their worth as easy, fun ways for people to share content and connect with others.

We ran this poll in September 2009, but it's time for an update. Let us know which light blogging tool you use and, if you like, leave a comment explaining why.

Posterous, the minimalist blogging platform, may have allowed users to post to their blogs via email, or even the specially-formatted Posterous for mobile devices, but now it's gone that one extra step. Posterous for the iPhone is here, allowing users to post, manage their settings, upload media and even geo-tag their updates.

The app allows users to post publicly or privately to any number of different Posterous sites they control. In addition to multiple sites, the new app will let you choose whether or not you want to auto-post your content to 26 different sites, from Facebook to Twitter to Flickr to YouTube and more. Posterous can even be an entry way to a Blogger or Wordpress site.

I downloaded the app and was up and running in under five minutes. Take a look (and a download) for yourself.

Today, National Public Radio (NPR) became the latest media group to join Tumblr, and I spoke with senior strategist Andy Carvin to find out how the organization plans to leverage the quickly growing platform.

"Part of what we do is experiment on different platforms, and it seemed apparent to us that there was a sizable number of NPR fans on Tumblr," he says. "It's less about pageviews and more about engaging a community that enjoys NPR."

Carvin says NPR is taking a very experimental approach to Tumblr in terms of curating content to share, engaging one-on-one with followers and determining how to voice the blog. He adds that he is eager to get feedback from fans, but that there is no "grand plan" for what they intend to accomplish.

Tumblr and the Media

By joining Tumblr, NPR also joins a growing list of traditional media outlets - including Newsweek, Life Magazine and Rolling Stone - attempting to reach fans on the popular service. But why is Tumblr such an attractive new medium for these organizations? Carvin says it's all in the visuals.

"Tumblr is a visual medium. Photos and snippets of quotes really stand out, while Facebook might have a sentence or two in a wall post and thumbnail with a link to a story," he says.

Why not use Posterous? "Who's to say we won't," Carvin says.

He believes Tumblr has attracted a media presence because of the ease at which a variety of media can be quickly presented on a site. It's this established media presence that led NPR to chose Tumblr over Posterous, at least for now.

"It's important to pick and choose your battles. It's easy to overextend yourself on every single platform rather than figure out sweet spots," he says. "We recognize that there's a large group of people online that love what we do [...] It's important for us to stay engaged with these folks at a personal level and not just a 50,000 foot level."

However for all of Posterous' hard work and bluster, it's been Tumblr that has grown exponentially over the past year. Take a look at these charts from Compete and Quantcast:

Source: Quantcast

Noting the usual 'grain of salt' about Web statistics, both Compete and Quantcast show that Tumblr has grown at least 3.5x over the past year. Posterous has shown some growth too, but it's been flat since May. More importantly, the gap between Tumblr and Posterous has widened considerably over the past 12 months.

The Keys to Tumblr's Success

The main factors in Tumblr's growth have been its first mover advantage (particularly important in an entirely new market segment, which this was when Tumblr started), celebrities and big media companies using Tumblr sites, and Tumblr's ability to socialize its service better than Posterous.

Fred Wilson, whose VC firm is an investor in Tumblr, claimed in April that "Tumblr is more of a social network than Posterous." While Posterous would debate that - it too enables users to follow people, comment and re-blog - the mere fact that Tumblr has many more users than Posterous makes it a more powerful social network.

Perhaps it's still too early to declare Tumblr the winner of this battle, but it would be a miracle now if Posterous usurped them. Tumblr has a large lead over its rival and all of the momentum.

Which light blogging service do you use? Tumblr, Posterous - or perhaps an innovative battler like Soup.io? Let us know in the comments.

The update is just for the standard desktop client, not the "super-swanky User Streams Preview version", but TweetDeck promises an upgrade for that is also on the way soon.

Two of our favorite new features, however, are "smart cross-posting for longer tweets" and support for t.co, Twitter's new URL shortener that is about to become the default across the network.

If you want to post an update that's longer than Twitter's 140 character limit, TweetDeck will let you, as long as you have a Google Buzz account. It will automatically truncate your update to 140 characters and include a link to the full text on your Buzz account. The only thing we wish here is that it would do the same with Facebook, instead. As for t.co, hovering your mouse pointer over a shortened link will now show the destination URL, taking away the mystery of clicking on a shortened URL.

In addition to all of those, TweetDeck has also added the ability to post photos directly to Posterous - a much requested feature - and support for logging in using a TweetDeck account, which helps to automatically add your accounts if you ever need to re-install.

A full list of additions and bug-fixes is available in the full changelog.

As for the campaign as a whole, Posterous' VP of Marketing Rich Pearson says the company is "thrilled at the results."

"It's too early to gauge the long term bump, but in the short term, it's been huge," Pearson told ReadWriteWeb.

With today's import tool launch, Wordpress joins services like Flickr, Tumblr, Movable Type, Ning, SquareSpace and Blogger - all which full under Posterous' definition of a "dying platform." At the launch of the switch campaign, Posterous used the phrase to openly call out its competition - an action that some saw as a misstep and a gross overstatement.

The debate was heated even further when posts discussing the issue were deleted from the popular news discussion forum, Hacker News. Some accused moderators of the forum - part of Y Combinator, a startup incubator from which Posterous graduated - of intentionally removing the anti-Posterous discussions.

Pearson says the company didn't intend to offend anyone with its campaign, but that the wording was no accident.

"As for the switch campaign, we knew we had to make some bold statements to break through the clutter but weren't intentionally trying to piss people off," he says. "We believe we have the best product so any type of head-to-head comparison was going to benefit us."

Posterous may have seen a bump in usage over the last few weeks, but its reputation may have been damaged by its choice of language. Whether or not it was wise to go toe-to-toe with over a dozen large competitors by calling them "dying platforms," potentially alienating thousands of users of multiple services - the company seems pleased with the outcome.

"We have nothing against our competitors - we're just playing to win," says Pearson.

So in many ways this is reducing Web publishing to its most basic form, devoid of new content. Is this "automated content manufacturing," as founder Paul Sweeney described it to me today, useful to people?

The use cases of Primal, according to Sweeney, include a teacher building a website of course materials for their students and a small business providing information to support their product.

In my initial tests today, Primal seemed a little raw - although the UI is slick. The brainstorming and 'find content' aspects of the product are essentially search features that surface keywords and media from sites like Wikipedia and Flickr.

What's most interesting about Primal is the publishing aspect, the webpage builder. This is well designed and easy to use. Within a matter of minutes I was able to 'author' a webpage about my favorite band, The Velvet Underground.

However, as noted above, it had no original content on it - which means it doesn't add much value to the Web as a whole.

Primal appears to be competing with other lightweight publishing services, such as Tumblr and Posterous. More so, the so-called Geocities 2.0 startups like Weebly and Yola. The difference is that Primal is much more automated than any of those services, which takes a lot of creativity out of publishing.

I asked Sweeney how he thought Primal compared to Demand Media, the content farm that is pumping thousands of pieces of content onto the Web each day. He acknowledged that Primal will also pump a lot of (unoriginal) new pages onto the Web, but he said that Primal content is architected by the end user and not the company.

Despite the rather hyperbolic terminology in the company's press release (an upcoming product called 'Primal Thought Networking' apparently "supercharges your thinking by remembering, organizing and connecting your ideas in your own machine-readable thought network"), the product itself is interesting because it takes Web publishing down to its very basic bare bones. Whether this is something that enough consumers need or want - and whether it's good for the Web - is yet to be determined.

Read on for graphs of engagement below. The same analysis performed here can be run on any sets of top-level domains using the newly released Postrank Domain Activity API.

Postrank measures engagement by comments to posts, mentions on Twitter, inbound links, votes on Digg and many other quantifiable metrics. All the numbers below are over the last 90 days. Blogspot, the domain for Google's Blogger blogging tool, still reigns supreme almost 11 years after it launched.

What's the takeaway here? I look at these numbers and think a couple of things. First, it appears that the world-changing democratization of publishing by the first wave of blogging tools has had some sticking power. Second, just because our early adopters' scene and the mainstream media are talking about Facebook and Twitter instead of "the bloggers" nowadays, doesn't mean that people have abandoned blogging. Finally, even though curation services like Tumblr and Posterous are pretty awesome, they haven't gotten as much mainstream mindshare yet as the old classics have.

I think these engagement numbers are a good snapshot of the state of the technology over time. I find it encouraging that there is such a thriving blogging scene still today.

What do you take away from these numbers?

Postrank is generally very useful and accurate, but the maze of social media links can sometimes be challenging to penetrate. Running Facebook.com and Twitter.com through the API turns up an unrealistically low amount of engagement with those domains. Both are reported to be roughly 3 times as big as ReadWriteWeb. I suspect the ratio is a little bigger than that.

Other Interesting Observations

What other domains are being talked about across social media conversations? Postrank made some interesting observations today, including:

Twitter users talk about Google, Facebook users talk about Yahoo

Honda gets talked about far more than Ford or Toyota.

For designers, inserting a "like" tag in a theme and adjusting the href attribute to whichever page they want a user to Like will create a Facebook-facing button for that theme.

Facebook's size, and the likely increase in its web gravity, is no doubt inspiring developers from horizon to horizon to include Like buttons and like features in their products.

Expect a significant upturn in Jack Horner references.