Not to be confused with Yahoo! Buzz, Google Buzz is a tool much like Twitter that allows you to share links, pictures and videos with all your Gtalk contacts. Positioned inside your Gmail account (if you have it, it will be listed among 'inbox,' 'outbox,' 'sent mail,' etc.), Buzz is essentially Google's attempt to take on Twitter and to a smaller extent, Facebook. It automatically sets you up to follow only the people you email and chat to frequently, but it also gives you the option to post your updates on private or public.
There's also the ability to connect to other sites you use, like Picasa, Flickr, Twitter and your RSS feed.
Automatically pulling images from links you post, it does seem to be a bit more fleshed out than Twitter, however, there doesn't seem to be a character limit, which could make things very cluttered after a while. Another thing that could make everything a little crowded is the fact that it sends notification of any feedback to your mail. Likes, comments and all the rest appear in your inbox.
Similar to Twitter's "retweet" function, Buzz will sometimes show you updates from people you're not following because a mutual friend has reposted that update. Say my brother recommends a post from someone in his office (we'll call him John Doe); this post will show up as an update from John Doe and clicking the 'Recommended' hyperlink will show you why it's appearing in my stream.
Check out the video below for more. If you're already playing around with it, let us know what you think.