I may be missing something, since I haven't tried all of them, but it seems that none of those platforms can be called an "asynchronous IRC"? That's the appeal of Twitter for me:
Oh, and like on IRC, technically minded people tend to gravitate to the platform. Is there anything except Twitter that would offer the same features? There used to be identi.ca, but seems like it's gone now.
Is it possible that software is not like anything else, that it is meant to be discarded: that the whole point is to always see it as a soap bubble?