I ran into this a while ago and thought it might be cool. Basically it recommends sites to you based on what you say you like and what other that share you interests have said that they like.
I haven't figured out how to use it as a marketing tool yet, but I have been able to find some need web tools. If you come across something once you better bookmark it though, because you might never find it again if you don't.
the Awesome Highlighter >> Highlight text on web pages
Firefox News : Speed up Mozilla Firefox