Until recently no one had taken it upon themselves to do concentrated, outsider examination of the News Feed - Top News versus Most Recent (both are filtered) - to see what's going on. Tom Weber staged a one-month experiment to unpack the algorithm, and came out with 10 of Facebook's secrets - and if you're crafty, a way to game the News Feed to ensure that you come up more often than others.
Search for your site URL and the results displayed will un-shorten all shortened links in tweets that link to your site. It does not matter what URL shortening service someone uses when tweeting about your site, BackTweets will resolve all shortened URL’s to display the ones pointing to your site.