After updating my xoom as well as my sensation, the option to view buzz posts and post buzz posts is gone. Not sure about the implementation in gmail as I never used it.
It's still unclear to me what application you are trying to view buzz in... if you go to the browser and go to buzz.google.com, you can see the buzz feed
Google Maps, the application found on tablets and android phones, use to have Buzz built in to the app as a layer that one could view. It would bring up all users in the surrounding area who would post. Its now GONE.