Photo: Fairfax Media | Getty Images Image 1of/12 CaptionClose Image 1 of 12 Jack Dorsey Jack Dorsey Photo: Fairfax Media | Getty Images Image 2 of 12 Happy birthday, kind ofSo March 21 may be the official birthday of Twitter, but if you couldn't even use it until July 15, 2006, how does that even make sense? Happy birthday, kind of So March 21 may...