Some features just make sense. Google Buzz is one of them. It's nothing new really. It's just Twitter integrated within GMail, and with commenting, it looks a lot like Facebook.
On most websites nowadays, you'll see somewhere on the page, usually at the top right corner, links to the site's RSS feed, Twitter account, and Facebook fanpage. I've always wondered why MySpace, being the second largest social networking site by far, isn't on that list.