The business Google is in is all about search and all about ranking the value of a page. This means it was only a matter of time before Google would show up with something like digg or a similar social bookmarking/ranking engine. This way google will not only be able to tell the people who use the search engine if the site they link to is interesting based upon a pagerank algorithm they are also able to check what the value of this site is based upon the social network of the person entering the search query.
In this form a social network will most likely be a little more wider than only the people you know and connect to with your Google profile. It will also include the people who have stated that they like the same pages as you do. This will possibly, read possibly, open a couple of new options for Google. They will improve their search and they expand the foundation for a social network. As we all know they are currently "at war" with Facebook and looking for ammunition.
This social bookmarking just came into beta testing and is called Google +1. In the below youtube movie you can see some more about this and who it works.
Google is running a site about the +1 option and this is telling us it will be available within search and within other websites on the web (not only google sites). So when it become available it will also be integrated into this weblog.