This afternoon Google unveiled a new social feature called Buzz. Some predicted it would be a Twitter-killer, but Facebook seems to be the company Google is gunning for.

Buzz should be familiar to users of either social media service: Paste a link in a box and the link's content -- photos, videos, headlines, etc. -- pop up and can be shared publicly or privately. It integrates with Picasa, Flickr, Twitter and YouTube, but not Facebook. Other users can read, comment and mark content as something they "like." It also offers location-awareness, which could make it a Foursquare-killer, too. (For more about Buzz, see the demo video below or visit Google's Buzz site.)

What role does Google hope to occupy in the social media ecosystem? Does the search giant want to coexist with or obliterate existing services? The mixed answer is apparent in how Buzz functions: it plays nice with Twitter, but doesn't interact with Facebook at all.

Facebook stands to lose users to Buzz, because of Google's traditional strengths and massive scale.

Buzz offers what Google does best: search.

Even as Facebook has become one of the largest drivers of traffic to Web sites, users have no way to search the stream of content their friends are sharing, which has helped make the Facebook "News Feed" experience somewhat overwhelming. Throughout the Buzz press conference, Google employees repeatedly stressed how the feature will increase the signal-to-noise ratio, exposing users to more relevant, interesting content. Buzz will recommend posts from like-minded people you may not be exposed to otherwise -- someone you don't know, but who shares multiple friends or interests with you. If you don't like it, click a button and Buzz will try to learn.

Google also benefits from is its large existing user base. Many people already use Gmail and Google Reader, which has a sharing feature of its own that will no doubt be integrated into Buzz. As Buzz grows, users already ensnared in Google's Web may find less need to use Facebook. That user trend towards centralization also explains why Facebook is allegedly developing its own e-mail service.

Google, of course, has struggled to grab a big share of the social Web in the past, so there's no guarantee that Buzz will succeed. But, unlike Google's past efforts, this foray into social comes not as a standalone product, but as part of one already widely used: Gmail. That, coupled with Buzz's similarities to Facebook, might help Google quickly pick up a big chunk of the market.

Here's Google's official introduction to Buzz: