Yeah, we'll see if they rely on general search or develop a trending topics system. I'm not sure about blocking either. Haven't seen anything for it. There's a lot on the security side of things that isn't obvious. The level of publishing security settings is greater in Buzz though, so you have far greater control over who sees what. I'd say out of the gate Buzz does significantly more than Twitter - remove 140 character limit, embed videos, links, and images, private and public group conversations, etc. It's a far more sophisticated platform, but Twitters success is likely due to its simplicity. If you ignore the biggie - expected use case, for a second, conceptually, they're different beasts. A Twitter stream is either private or public and people join and may be blocked. A Buzz post may be completely public (Google indexed, etc.), private to all your contacts/group list, or private to a subset. A stream makes less sense when you have five posts and none of them are viewable by the same people. Facebook is kinda similar, but last time I was on it far less granular. But again much of this confuses me. Not sure how your contacts publishing settings affect viewing your posts and how contacts of contacts interact. Would have been nice of Google worked a bit on documentation before launching a product that conceivably outs a friends contact info.