Google today launched Buzz, a social networking module that sits on top of Gmail and allows users of the webmail program to share photographs, links and videos with other Gmail users.
The news comes just days after US-based online analysis firm Hitwise revealed that during 2009, Facebook had become the biggest referrer of news content - beating even Google News.
In the readwriteweb blog, Marshall Kirkpatrick called Facebook the "promised land" for publishers.
"Facebook is about 10 times as big as Digg or Twitter but so far has been less focused on sharing and clicking links. If Facebook can become the go-to place for hundreds of millions of users to find news (and that seems quite likely, doesn't it) then the company is going to be in a very good position," wrote Kirkpatrick.
Google has been developing the social networking element for some time and is made possible because, according to a Google Australia blog entry, there has "always been a giant social graph underneath Gmail", which means that Buzz-enabled Gmail users will find they are already "following" the people they regularly contact.
Buzz will communicate with Flickr and Twitter, as well as Google properties such as YouTube and Picasa, but it is incompatible - for now - with Facebook.
Google has "relied on other services' openness in order to build Buzz and claims to be working on making Buzz "a fully open and distributed platform for conversations".
"We're busy working on a full read/write API for developers," the blog entry said.
The mobile version of Buzz, which tags posts with location-based data to "answer to the question 'where were you when you shared this', could also spell doom for foursquare, which provides a similar service and has steadily been growing in popularity.
Google expects Buzz invites will be sent to all Gmail users by the end of this week.
Facebook did not return requests for comment.