By Alex Iskold
Last week Apple's iPhone made a stunning debut. There are very few people who were not blown away by what Steve Jobs showed to the world, from the stage of MacWorld 2007. The irony was that beforehand, we didn't know what exactly the iPhone would be, but most of us knew it was coming - because there were rumors and lots of blogosphere chatter about it in the weeks and months leading to the announcement.
Today's blogosphere is a unique playground for trendwatchers who are seeking to find out what's wired or tired. Check out this image of the Blogosphere core, from the fantastic DataMining blog by Matthew Hurst:

Technorati is much more than a vertical search engine for blogs. It's a service that provides indispensable tools for bloggers, readers and trendwatchers. Technorati keeps the finger on the pulse of the blogosphere and gives us access to the news, both new and old. Perhaps the most interesting tool that Technorati offers to trendwatchers is the historical chart. Here is the chart of all blog posts mentioning social bookmarking over the past year:

If you believe that high blogosphere activity indicates popularity, then this chart shows that social bookmarking is wired. You may recall that in our recent post about Trends in Seth Godin's Alexa data, we concluded that social bookmarking sites grew substantially over the last six months. So both data sets lead to the same conclusion.
We can also use Technorati charts to compare trends. We need to be a bit careful about this, because each Y-axis has different numbers - but otherwise it is insightful. For example, people have been talking about the rising popularity of virtual worlds. Let's see how this upcoming trend is comparing against its "daddy", social networking.

Virtual worlds is on the left, where maximum mentions is 200. Social Networking is on the right and maximum mentions is 1200. So what can we say about both trends? They are both wired, although it seems like virtual worlds has only just started to pick up momentum - while Social Networking might be peaking (but this is not so clear).
Next, we compare the companies that make up the social networking trend. Below are Technorati trends for MySpace, Facebook, LinkedIn and Orkut.

MySpace is above on the left, where the maximum number of mentions is 30,000 (Whoa!). Facebook is on the right and the maximum number of mentions is 2,200.

LinkedIn is above on the left and the maximum number of mentions is 240. Orkut is on the right and the maximum number of mentions is 800.
So if we ignore the scales for a moment (at this point MySpace violently protests), we see that all of these trends put together explain the overall growing trend for social networking. Also, these charts reveal fairly substantial events - for example you can see in Facebook's chart when rumors started to spread that Yahoo! might acquire it.
Finally, notice that people are starting to talk more about LinkedIn. Curiously, this is at odds with the Alexa chart that was part of our recent analysis - at least if you believe that page loads correlate with mentions in the blogosphere (they should).
Most of the things that we have looked at so far have been wired. But the next one is not. And it's Ajax.
Looking at the chart below, we see that the Ajax buzzword is getting tired. This is probably not surprising to developers, because we are seeing the rise of libraries like jQuery that hide Ajax and take it to a whole new level. So the new trend we can perhaps call MetaAjax.
Of course no blogger can resist ego surfing, or in this case ego trending. It is human nature to feed the ego with mentions of cross links. Here is my modest chart (I take comfort in the fact that my presentation at DEMO went well).
Technorati allows you to track a single trend. Comparing two trends is not easy because of the difference in scale. For comparisons, you should head over to Blog Pulse, a service offered by Nielsen BuzzMetrics. Also Google Trends is a useful comparison tool, but in this post we'll focus mainly on BlogPulse.
In addition to basic blog search, BlogPulse allows you to compare up to 3 trends. For example, below is the comparison of Social Networking vs. Virtual Worlds over the last 6 months.

There are a few things to note. Firstly, BlogPulse shows you the trend as number of mentions relative to all blog posts. It is likely to be the number of posts mentioning the term divided by the total number of posts that day. The fact that this is a relative number is a good thing, because it allows us to distinguish the growth due to rising number of blog posts, from the growth due to popularity. Another thing to note is that this chart does not quite agree with what we have seen on Technorati. For this reason, it is really important to understand the data and the method behind any chart. Given the two, it appears that Nielsen's data is normalized and hence more accurate (assuming there are no bugs).
Here's the same trend comparison in Google Trends (for 2006), which shows a similar pattern:

We close this post by pointing out that Blog Pulse has a page that features interesting trends across topics like news, entertainment and technology. There is also a section called 'Bizarre stuff' that, naturally, caught my attention. The first featured trend there was comparing mentions of the Seven Deadly Sins:

Now here is something interesting... the two most popular ones are pride and anger. If only envy was up there too, as then we would be able to nicely explain the origins of Ego Trending!
On a more serious note, quantitative analysis and trending are really important tools for measuring success, explaining the past and preparing for the future. We are eager to hear your trending methods, tools and the sites that you find useful. Let us know in the comments!