Twitter's stock slid significantly in April when its earnings report leaked out early, and in a likely-related move, now it's changing CEOs. Dick Costolo is out (at left in the picture above, taken during the company's IPO), although he will remain on the company's board, while founder, chairman, first user and former CEO Jack Dorsey (at right) is taking over again on an interim basis. He will stay on as CEO at Square while a search committee -- including yet another former Twitter CEO, Evan Williams -- searches for a permanent replacement. Of course, that the report leaked isn't the problem, it's the user growth, which couldn't match other social network stars like Instagram. Investor Chris Sacca recently published a lengthy blog post about "what Twitter could be" and despite a number of changes over the last year, it appears many of the folks owning shares had different ideas than its (as of July 1st) former leader.
Update: According to Costolo (on a conference call) he initiated discussions with the board about stepping down "late last year." Jack Dorsey followed up by stating that the change has "no connection" to the company's near term results.