Mashable's intro: http://mashable.com/2009/09/21/mashable-trends/
The idea is it pulls in a Twitter account's timeline, unpacks short URLs, collects Flickr/TwitPic/Youtube media, matches statuses against Twitter's trending topics, and ranks top re-tweeted URLs that point back to Mashable's site.
In other versions of our app we rank links being shared and other neat bits of data. More on that later.
They always say build the app you want for yourself and this is definitely it. My own tracker runs on my laptop and every day I get a growing list of trends and links of people I'm following.
Last week I was pretty well sick of Kanye, you jerks.