As soon as Google Buzz was announced, people around the Internet began questioning the service. Was it giving away too much information? Potentially exposing your Gmail address? I worried that I would unintentionally share content with someone I didn't want reading my feed.Google was listening and is now responding to concerns via a blog post. Included in the immediate changes are more visible privacy controls both during the Buzz setup process and on your profile page. Also included: the ability to block anyone following you, allaying my concern.
Google also mentioned it is thinking of operating Buzz independently of Gmail, so conceivably anyone could participate, not only those with a Gmail account. While I don't think any of the new changes are necessarily making content more private, they are making it easier to understand just how much information you're sharing with contacts. And if you're still concerned about privacy, you can always turn Buzz off completely.
Update: Looks like Google has responded with a statement saying they can't confirm the separation between Gmail and Buzz just yet.