a twitter clone is a good idea, but a a twitter "Ning" is a better one. I would prefer someone make something that works. Something public domain that people would pay those that had the know to fix. That way everyone could have their own twitter.
I go to the optimal opportunity to share. del.icio.us All this talk of buying Yahoo. If Yahoo bought friendfeed there would be no need to sell. think about it. Yahoo suffers from fragmentation and no centralized core.