I often get into a situation in where I search information I have seen somewhere in the Internet. It could be a blog entry, a comment in a forum, some business website etc. When I go to Google, I always get results based on statistics to which all users contribute. But I ususlly search for hits that I have already seen. The more often I have seen them, the higher the ranking should be. So, a good approach for my problem would be:

• Track the pages which I have visited. That could be done via a Firefox plugin. This has to be stored somewhere.
• When I add a search term, it should check the pages I have seen first and then propose hits I a am not aware of.

Do you know any service that provides this feature? Probably something from Google?