I thought Google Buzz launched today but I don't see the link on the main page yet. Maybe later today or tomorrow?
In the meantime, below is a video about Google Buzz. Its getting a late start compared to Facebook and Twitter but I think Google may have some other ideas in mind for the future. For instance, I know the two social giants are huge in the U.S. but what about India China and Russia? Google does own Orkut which has 100 Million members concentrated in Brazil and decreasingly India.
Here is a long list of the world's social network websites.
Only time will tell if Google can catch up and surpass the biggest players. I'm not one to doubt what Google can accomplish, especially in the long run. They seem to have the Chinese idea of measuring success in decades, not months.