Thanks very much for the feedback.

What I fear most finally comes true -- not even HN users can immediately figure out how to use the site (which was purposely left out from the brief)...

How about some hints like you can get all news regarding social networking websites:

  http://bit.ly/dc6ko

or compare DISQUS with Intense Debate:

  http://bit.ly/3Qhr9s

Now I definitely need to rethink the usability issue.