Topsy indexes every public tweet: Who first mentioned Justin Bieber? Ever wondered who first mentioned Justin Bieber on Twitter? Now you can find out. Social analytics firm Topsy announced it has indexed every public tweet that has ever been sent out and has made the information available to the public -- a feat no one else, including Twitter, has been able to accomplish. Topsy specializes in providing social data to companies, so it had already indexed many public tweets going back to July 2010. But Wednesday's update beefs up the company's indexing service with all public tweets going back to 2006, when Twitter launched and was actually called "twtter." That's good news for Twitter users, who know all too well how hard it can be to search for a tweet after a few weeks have passed since it was sent. Twitter's search algorithm emphasizes recent and popular tweets over others, and with 400 million tweets sent out each day, individual tweets can easily be lost in the shuffle. Users can head to Topsy's website to start searching for tweets. The company said users can search for tweets based on individual accounts, hashtags or key phrases or words. I searched my own handle, @sal19, and was embarrassed to find some of my early tweets. Below is the first tweet I ever sent out, according to Topsy. Topsy demonstrated its updated search tool for me Tuesday, and among the terms we looked up was "Justin Bieber." The teen is the most followed person on Twitter -- and found that you can blame Twitter user @bdray for being the first to mention "Justin Bieber," when he did so five years ago, according to Topsy.