After giving their official blessing upon the Blackberry twitter app (developed by RIM), it looks as if Twitter has come to the conclusion that anointing RIM’s creation as the official app was a dumb idea after all (via Mashable).
continue to focus on what is best for users and we will work together to make sure that we are creating more opportunities for the ecosystem on the whole. We will also admit our mistakes when they are made and the Blackberry client should never have been labeled “official”. It has since been changed and you won’t see that language used with Twitter clients in the future. (Ryan Sarver of Twitter Development Talk)
The Blackberry app pretty much boasts features that are considered standard for iPhone Twitter apps (like direct messaging, uploading images, list support, blocking spammers, etc.), although there does not appear to be any support for video uploading (so BB fans will still have to use TwitVid).
Blackberry intends upon launching this app for free (and effectively kill off a few developers as well), and should help them compete against the iPhone whose apps are famous in the twitterverse (especially Echofon, Tweetie and Twittelator).