Google have just launched an additional service called SearchWiki for those with a Google account. Basically you get to add notes to search results or move around search rankings. Google will remember them when you search again and you are logged into your account. That is, you won’t see them if you’re not logged in and your changes make no difference to what others see, unless they ask to see what notes other people have made.
It’s an interesting development for search because it will not only mean you can use notes to remember things for later, but also improve Google’s ranking and searching ability. I feel sure that the notes or amount of notes or something similar will eventually feed into Google’s own algorithms. So, not only will people be complaining that Google is making us dumber, but also that we’re making Google smarter.
You can also have a look at how SearchWiki works.