The database is populated with the people who have signed up for Gist's public beta and their contacts. There are 100 million profiles of people and companies behind Gist's wall, collected over about a year. Now, Gist wants users to "claim" their profiles by updating their own data (and potentially making some information public).

You may have encountered sites like Intelius, which built profiles for users by scraping publicly available data they've submitted elsewhere, slotting it into a directory that users have no control over, and saving it forever. Gist doesn't do this exactly, but it gets your name from someone in your social graph, connects it to your social media profiles and slots in your recent blog posts. The "vast majority" of the 100 million people in Gist's directory don't know they have Gist profiles, CEO and founder T.A. McCann said.

Example of a Gist public profile.

But unlike Intelius, your profile is only visible to Gist users, and to some degree, you can take control of it. Gist is encouraging users to "claim" their profiles by registering, picking a URL for your profile and deciding what information to make public. The resulting profile is where Gist most resembles LinkedIn and will be indexable by search engines and visible to anyone with the address, similar to Google Profiles.

Here's the rub: You can control what you make public, but Gist users will still see a slightly different profile for you, which they can update with your private blog, personal Flickr and even excerpts from your recent email conversations. Gist uses this user-submitted information to "crowd source" its database, which helps ensure that information stays up to date.

Google Reader meets your Rolodex

Gist is useful for professionals such as marketers or journalists who have to manage a big network of contacts. But it's more than a database of information about people with links to their social media profiles. Gist also has a space for you to tag a contact, write notes about her, shows your contacts in common from various social sites and display her recent blog posts or Twitter updates.

Example of a profile you would see after you login to your account at Gist.com.

Gist will also assign a level of "importance" for your contacts, editable by you, which it factors into a Facebook-esque "News Feed." It's a consolidated inbox, McCann said. We called it a personal relationship manager.

Gist is a powerful, usable alternative to competitor LinkedIn, the business-oriented social network which has been criticized as stale, hostile to developers and fumbling new features (see our post, "Why Does LinkedIn Keep Doing Things That Don't Make Sense?").

A platform and a plug-in

You can integrate Gist into your existing workflow by installing a plugin for Gmail, Outlook, Salesforce, Lotus Notes or the iPhone or Android app. It's also available as a Google Apps gadget and an email digest. McCann said a robust application programming interface, or API, is already in priavate use and will eventually become public, but declined to give details.
How Gist works in Gmail.

Gist is a strong competitor not only to LinkedIn, but also to apps like Rapportive, a browser add-on that displays user profiles in Gmail and expensive databases of people and contact information like Vocus. Gist raised $4 million in July on top of $6.75 million last year. McCann plans to monetize by providing premium services to users who want to see information from paid databases like Hoovers and enterprises that want to integrate Gist into their own software.

So is it a LinkedIn killer?

The crowdsourcing element is a little unnerving. Gist lets anyone submit information about you, and anyone you've emailed can upload the subject lines of your emails and who you've cc'ed (note: Gist does not make content from your emails public). It's all information that you've made public in some way or another, but it's a little scary in the aggregate.

Gist is a formidable LinkedIn challenger, and perhaps it deserves to win. We love the library of plugins and extensive functionality. But Gist's automated and crowd-sourced database is a little too slick - if only because it reminds you that information you share on the Web could end up anywhere.

We'd love to hear what you think about Gist. Have you claimed your profile?

Update: Google has now closed this loophole. Here is a statement we just got from a Google spokesperson:

Blogger harmonyguy helped us discover a bug that made it possible to discover a user's email address based on their numeric profile ID. Our engineers worked hard to address this issue and it is now fixed.

Security blogger The Harmony Guy just told us about how this hack works. While the way to reveal these addresses isn't obvious, you can easily follow along and try this method out yourself.

How does it work?

First, you simply copy the numbers from a user's Google profile and then append these numbers to http://picasaweb.google.com/[numbers].

For some users who haven't customized their Picasa page, the username (which is also their Gmail address) will come right up. If the user has customized the account and added a nickname, you simply have to replace the URL in the address bar with javascript:alert(_user.name); and a small pop-up window will show you the username.

Caveats

It's important to note that this only works for Google users who also use the Picasa web service. This, however, is likely a large percentage of Gmail users.

How to Protect Yourself

In Picasa Web Albums, go to the settings page and add a new username. Then, select the new username for your gallery URL. As The Harmony Guy points out, you may also want to edit your nickname.

Is this a major issue for Google? Probably not. But given the ruckus around privacy, Buzz and Google Profiles these days, it is disheartening to see that it is this easy to circumvent the only way to hide your Gmail address from public view. After all, if you want to use Google Buzz, Google forces you to have a public profile.

Making Your Email Address More Useful

You can think of WebFinger as an email-centric cousin of OpenID. While OpenID associates your identity with a URL, WebFinger links your identity to your email address. WebFinger can store metadata about your account and make it publicly accessible. This data can include your public profile data, information about other services that are used by this email address, a URL to your avatar, or - if you choose so - a declaration that this address doesn't have any metadata associated with it. The WebFinger metadata can also point to an alternative identity provider, which can be an OpenID server.

Update: we should note that while webfinger accounts look like email addresses - and often are email addresses - they can also simply point to a webfinger account that isn't actually an email address, too. It could just point to a public profile.

Currently, there are not a lot of user-facing projects that expose this data, but you can find a small demo service written by Google engineer DeWitt Clinton here.

Adding Value to Google Profiles

With Buzz, Google already put a lot of emphasis on Google Profiles and today's announcement increases the value of these profiles even more. It's important to note, though, that WebFinger is an open and free protocol, so any email service and identity provider can implement it. You can find more detailed information about the WebFinger protocol here.

Image Credit: Flickr user purpelslog.

This could be a fascinating example of using multiple services together in a way that adds value to users' social lives and incentivizes them to contribute personal data to the system. It would be if anyone but geek early adopters filled out Google Profiles. Give it a try, though, and let us know whose birthdays appear for you. Old friends and family? Or just geeks online?

Look how buried this is though! The only thing more buried is the Google Profiles themselves that this birthday data is drawn from. We found out about the new birthday feature via Brad Linder.

Why is Google not better surfacing Profiles and the most compelling social data that can be drawn from them? It makes no sense. Sports calendars are now being promoted on the top of your Google Calendar page. Are more people really drawn to sports than to the birthdays of the people they are in regular contact with? Birthdays are important.

We have our concerns about Google's broad knowledge about many different parts of our lives - but the Google Profiles product has a lot of potential to do awesome things. The company should give the Profiles product the respect it deserves.

In the meantime, it's quite easy to add a few of your friends' birthdays to your Google Calendar. It's low cost in terms of time, high pay-off in social connectivity. We just thought you'd want to know.

Profile options are already being changed in response to popular requests; a new section of contact information that you can expose only to selected groups of people has just been added, for example. This opportunity to influence how Google describes you via your profile could be a very important one, and it's worth your while to take a look at the discussion and cast some votes for and against ideas. As we write this, only 600 people have so far.

For example, Google Social Graph API creator, Brad Fitzpatrick, posted a request to add rel="me" markup to the profiles so that the smart applications (like this one) can tie together all the accounts from various websites people list on their Profle pages. Several other people asked to have music playlists or GTalk IM status messages included in Google Profiles. Others asked that Google Profiles by tied to Gmail contacts for easy viewing in other applications.

There's a lot of optional fields you can fill out in a Google Profile now. You're asked to list where you work, where you went to school, where you've worked in the past, what your "superpower" is and other information. When Google Profiles got pushed to center stage yesterday, we voiced a concern that most peoples' concerns about what shows up when people search for their name on Google is too much information. Being told that the answer is to give Google even more info about us, in order to have any influence on our public appearance, seems ironic at least.

The Potential For Innovation

The potential for innovators to make use of these profile pages, if they are marked up well and made available, is really incredible. Just imagine: Dear Google, please show my software to all the people you know with Google Profiles who have listed their Delicious accounts, have bookmarked in Delicious more than 10 links around the web with one of 10 common food-related tags, who live in California, Oregon or Washington, and who have YouTube accounts as well. I want to gather a list of the videos that are most popular this week with food lovers on the West Coast.

That might be a pipe dream, but it certainly wouldn't be technically difficult if markup was good, the data was exposed well to developers, and Google Profiles caught on well enough to build a large data set. Imagine the incredible variety of potential permutations of profile fields, cross referenced with data found on linked-to third party websites, that such a scenario would offer.

There are simple issues and there are complex ones that come up when public profiles become important on the biggest information discovery site in the world. There are privacy concerns and there are wishes and hopes for data-centric innovation. Who doesn't have thoughts about how they would like to be described to the world? Now's your chance to vote on it.