I turned off Google Buzz the moment I saw its advertisement blocking my gmail page. And I had to google it to learn how to turn it off. And I thought only Yahoo! and Microsoft did stupid things when it comes to email.
People, your email is not your social network. Just because you own a phone number, that doesn't mean you have to invite everyone you ever called to call you to say hello, nor does it mean you are interested in hearing other people's calls. The worst thing is, what Google Buzz is doing is to equivalent to publishing the names of a few dozens of people you've recently called to the entire world.
A few weeks ago, I logged into my long deserted Yahoo! email account to see if there was still anyone I knew emailing to that abandoned address. I used to do that every few months. To my horror, I discovered I was enrolled in many social networks I didn't care about without my prior consent. I could even saw updates (equally inadvertent) from some contacts that I really only contacted once in like... what, 10 years ago? I immediately cancelled my already disused Yahoo! email for good. Microsoft does similiar things if you happen to use both its whatsitsname Messenger and its Live Mail.
Google's email used to work for me very well because that was the only service that didn't try to be a sucker. For all its good reputation on thwarting email spam, this is the biggest surprise I've had from them yet.
Update: What annoyed me was how Buzz was deployed. It was opt-out by default, not opt-in. I can understand the rationale Google wants to do this. Books like Nudge show opt-in and opt-out can make huge differences. Also, the nature of web app means new features are enabled automatically to everyone. The problem lies in the fact inadvertently joined social network can disrupt your ongoing design to compartmentalize your communication channels.