Carbon for Twitter - Android Apps on Google Play. There are many Twitter clients out there for mobile users. Most users settle on one, and the rest fine their own audience. Carbon, however, has been promised for so long that it might have difficulty gaining a user base now that it is finally available. It is pretty, if you like dark themes. And, it combines all of the Twitter feeds in one smooth interface. However, I reserve judgment until I live with it a while. If you have been waiting, here it is.