Paul Haddad writing on Tapbots Blog:
A lot of our Tweetbot for Mac Alpha users have worried about what’s going to happen to them now that the Alpha has been pulled. A few folks have suggested that we release a new version but without the ability to add any new accounts, we thought it was a good idea and have done that.
There’s lots of bug fixes, so if you’re already using the Alpha go ahead and grab the new beta from the aforelinked page. The real news here is that because of Twitter’s recent API changes you will no longer be able to add or reauthorize Twitter accounts using the beta. I really hope that Twitter realizes how this impacts developers. Twitter became what it was because developers were building on it, they shouldn’t stifle that innovation and potential user growth.