First Jack Dorsey was CEO and Ev Williams was chairman. Then Ev took over as CEO and Dorsey became chairman. Now Dick Costolo has been promoted to CEO, Ev is just a "co-founder" who's "focused on product", and today Nick Carlson reports that Dorsey—who still heads Twitter's board despite going off to co-found Square—is now back at Twitter part time, to help "fix" their product.
Note that none of these roles have been held by the third co-founder, Biz Stone, who remains Twitter's "creative director." Ostensibly he's also been focused on the product. Now the product needs fixing (or even more focus?), but Biz isn't being promoted or demoted to anything, so I guess whatever's wrong with Twitter isn't his fault.
Here's what I can tell you about this mess (which is probably a mess, but is being spun by all sides as purely voluntary, and about making something awesome even more awesome):
Also, as of Chirp (which came right after Twitter acquired Tweetie and hired Loren Brichter) there were still plans to develop and ship a new version of Tweetie for Mac. As of now, Ev Williams has said Tweetie/Mac is not under active development by Twitter, which is to say Loren Brichter may or may not be working on a new version, but if so he's doing it on his own time, and because the source code is owned by Twitter he probably can't charge money for it.
Meanwhile, they've abandoned plans to move Tweet storage to Cassandra, and their transition to a new unique ID scheme for Tweets has been rocky at best.
Every one of these mid-course changes makes sense in isolation; I don't mean to suggest otherwise. (Though we'll see just how uncommitted they are to Twitter for Mac when the Mac App Store launches in a month or two, and they have an opportunity to put Promoted Tweet ads onto every MacBook Air in the world.) These personnel changes and all this vague talk about "product" "focus" make me wonder whether there is a sane direction for this company, and if any six-month (or hell, three-month) plan they offer up can be trusted.