If you’ve ever wanted to search for something on Twitter, you likely went to search.twitter.com. That’s all well and good if you’re only looking to search on one source. What happens when you want to aggregate results from Twitter, Upcoming, Pownce, Delicious, Flickr and 12seconds? You use Social Mention.

Social Mention is a social media search engine that searches user-generated content such as blogs, comments, bookmarks, events, news, videos, and micro-blogging services.

These searches happen in real time. One query returned a result that happened less than 3 minutes ago. This service is powerful and relatively fast, given the breadth of sources it uses. I first came across it last week in the midst of getting hammered from its Mashable mention, but today it’s much more responsive. There’s also a “Hot Conversations” section showing users what’s buzzing right now.

By harnessing the power of the API, you can actually build an RSS feed on whatever criteria you want. It looks like Yahoo Pipes is the driver behind the aggregation for RSS. The main drawback is that you’re aggregating literally anything that matches your criteria, so there will undoubtedly be some noise on the line. It’s a minor (inherent) drawback, and most people will be able to tolerate it.

One area I feel there could be improvement on is the classifications (Blogs, Microblogs, Comments, etc). The first thing I noticed is that there isn’t an “All” category (though you can have one via RSS). I’d rather not click through each category and check them out individually. Also, I’m not sure which sources get lumped into which categories. For example, Twitter shows up in both Blogs and Microblogs.

Accounts to follow:

@socialmention, @jonnyjon (Twitter) or jonnyjon (FriendFeed)

Here is the full list of supported services