Official Google Blog:
“Google Buzz is a new way to start conversations about the things you find interesting. It’s built right into Gmail, so you don’t have to peck out an entirely new set of friends from scratch — it just works. If you think about it, there’s always been a big social network underlying Gmail. Buzz brings this network to the surface by automatically setting you up to follow the people you email and chat with the most. We focused on building an easy-to-use sharing experience that richly integrates photos, videos and links, and makes it easy to share publicly or privately (so you don’t have to use different tools to share with different audiences). Plus, Buzz integrates tightly with your existing Gmail inbox, so you’re sure to see the stuff that matters most as it happens in real time.”
Hat Tip to beSpacific
UPDATE: Questions have been raised by users about Google Buzz and the privacy of their email correspondents, specifically about “autofollowing” disclosing who you email and who emails you.
See: Lawyers…Careful with Google Buzz
See: Google’s Statement on the issue
Finally: Google Abandons Autofollowing