Google already knows far more about your website than you do. They know exactly how many people subscribe to your RSS feed and how often they actually read your articles. They know how many people visit your website and exactly where they come from. Google even knows how much you spend on marketing and how much money you make. Knowing exactly who likes your site and which pages they bookmark is just another piece of the puzzle.
Search engines follow people. If thousands of people bookmark your sites then Google has to take notice in the same way as if thousands of people link to you.
Sites such as Digg, Reddit & del.icio.us send a huge amount of traffic, not to mention links. If Google gets this new social networking system right then a listing on the popular items page could send a thousand times more traffic than Digg, imagine trying to keep your server running during that.
By far the most interesting feature of the shared items system is the integration with Gmail. Bearing in mind Gmail automatically adds people to the address book most users have built up hundreds of contacts and will have a ready made network of friends on the Google Shared Stuff platform. Its like joining Digg and having 500 friends already.
In fact, the Google system is much better than Digg because you already know most of the friends in your network. You probably know some of them in real life. Your Google Shared Stuff page will become a resource where you can share stuff with your offline friends rather than having to make a new set of friends like most social sites.
Each user has a page to show off their shared stuff. If you can build a reputation of finding really cool stuff every day then people will visit your page to see what sites you have bookmarked. Some might even subscribe to your shared items RSS feed. Once you build this reputation its quite easy to send traffic to your own sites.
The Google Effect
If Google really wants to make a go of this service all they need to do is link to it from Gmail or even the Google homepage and it will start getting more traffic than Digg and all the other social media sites put together. Watch this with interest over the next few months.