Do you want to promote your website? Instant Buzz is the best system I've come across. Normally participation is by invitation only (I was lucky enough to get an invitation), but they're opening it up to the public from the 17th to the 20th of December:
InstantBuzz All I can say is that the results for me so far have been superb. Lots of 'traffic' and lots more subscribers - it's even pushed my website up in the overall Internet ratings.
Be sure to install it - it's very easy to use. It puts a thin toolbar on your browser but don't worry, it's completely harmless to your computer and you can get rid of it very easily if you don't like it.