Google Plus 1, +1

It will be quite easy to identify informative sites in the clouds of tons of pages.

Like facebook "Like this"

An additional web recommendations criteria like Alexa ranking,Google Pagerank etc.

An easiest way to encourage good websites to the world.

"Use +1 to give something your public stamp of approval, so friends, contacts, and others can find the best stuff when they search. Get recommendations for the things that interest you, right when you want them, in your search results." Source:Internet