Created wikipedia.

From his wikipedia entry: "Writer Rogers Cadenhead drew attention to logs showing that in his edits to the page, Wales had removed references to Sanger as the co-founder of Wikipedia."

I was involved with wikipedia at the time of creation (and the whole gnupedia vs nupedia debate), and Jimbo was the driving force. Larry undoubtedly played a major role as editor-in-chief but from the very beginning it was clear Larry was subordinate to Jimbo (although that doesn't necessarily mean he wasn't a co-founder of sorts).