Re: Google Buzz
I guess not many here use Twitter, but if you did, you'd see that Buzz is directly competing with that offering - and it's a richer version of Twitter since it allows direct embedding of media into the buzzes (assuming that's what they're called in the buzz world... analogous to tweets).
My only issue is that if we start seeing similar apps being developed for Google Buzz through an API as we've seen with Twitter, I'm just not comfortable giving a third party access to my buzzes within my Gmail.