The Twitter-analysis firm Topsy now allows you to search through tweets going back to Twitter’s 2006 debut. Topsy used to allow searches back as far as 2010, Vindu Goel writes in The New York Times
. (Some reports say it went back as far as 2008.) Twitter’s own search, as Goel writes and anyone who’s ever tried to find something through it can tell you, is not as robust.