Google this week 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.
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.
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.
