Seth Godin commissioned a massive list of nearly 1000 Web 2.0 sites with live ranking data of popularity and traffic. The list is an amazing resource for blog marketers looking for new sites to interact with based on the traffic those sites receive.
Check out Seth Godin’s Web 2.0 Traffic Watch List and see if you don’t find scores of sites you’ve yet to explore for traffic and link building efforts.
The list also shows who has dropped a lot in the last 6 months in traffic, which should help you assess whether your involvement in those sites for viral marketing is still worth the trouble.