Here's one for the "Who Knew?" files: the news media's attention to the sub-prime fiasco rises and falls in step with its fascination with Britney Spears. Coincidence? I think not! I would not have noticed this linkage had it not been for Trendrr, a fascinating site that recently went live. An offshoot of Wiredset, a New York agency that specializes in promoting media through the Web, social networks and mobile carriers, Trendrr lets users assemble and compare data from a dozen sources (more to come soon), including Google News, Bit Torrent, eBay and YouTube. It also invites users to request new sources or submit their own. For example, you might want to gauge interest in a particular band by seeing how often people were posting videos of that act on YouTube. Or, if you were a studio, you could graf how often the trailer for your summer blockbuster was being played on MySpace.com vs. YouTube vs. DailyMotion. My examples don't do Trendrr justice, so click here to check out the site's most popular trend-mapping exercises. Then try creating some of your own.