I for one disabled it, because before I knew it, google was buzzing/spamming a few of my web activities.
I think they're bent on getting a bit of the Twitter and Facebook pie. Its failed with Orkut and I think this privacy breach from Google is a huge dent in the Buzz launch.
"Google decided that, rather than invest its ample resources in helping to preserve a free Internet and boost the free market overall by working against the FTC, it was more politically advantageous to build an alliance with the agency."