Google Admits Buzz Wasn’t User Tested Prior To Launch 

News flash: Googlers and Gmail users have different ideas of how social software should behave! Says Todd Johnson, Google's product manager for Buzz:

We've been testing Buzz internally at Google for a while. Of course, getting feedback from 20,000 Googlers isn't quite the same as letting Gmail users play with Buzz in the wild.

Not that user testing is that reliable or critical, but it does seem like a good idea for (say) grafting a social networking product onto people's private email accounts.