I think the use cases of Buzz and something like Fridge are very dissimilar. Buzz allows you to subscribe to individuals; although when you post it's one->many, fundamentally what it's promoting is a lot of one-one connections. Although Buzz makes it a lot easier to have a group conversation than, say, Twitter (which frankly sucks in a lot of ways, but was first), it's not really a group tool.

I agree about Google Groups getting ignored; it would be nice if the eventual Google Competitor to Fridge was built on an upgrade of Groups. Perhaps one that split off the Usenet part of Google Groups completely; mixing in proprietary Google Groups and Usenet via Google wasn't ever a good idea.