Didn't this already happen, and last time we got identi.ca? Why spin off a new microblogging site when there already is one rebel site full of open source devs? What does rStat.us get us that identi.ca didn't?
It's pretty great stuff -- I have a StatusNet instance on my website, and people can follow me from other StatusNet instances, I can follow them; it really is decentralized Twitter.
'Because Twitter is mean' doesn't pull many users.