1. Posts/Buzzes are inherently public to the world
2. Posts/Buzzes are discoverable via search
3. You have no control over who subscribes to your blog via RSS, just as you have no control over who "follows" you.
4. You have no control over who puts comments on your blog/buzz. This gives hints about those who might be subscribers/followers, but not really because commenting is open to the world.
One non-similarity is that with a blog you don't know how many people are subscribed; in buzz, you do.
