Google now is making a big and new social feature called "+1" that is similar to facebook "like" button, and intergrates directly into the most popular search engine in the world.
For all the users who opt into the +1 button experiment in google lab will start seeing the +1 icon next to each link in google search results.
Google also defines the action as a public stamp of approval, when you +1 something, your name becomes associated with that link in search, on ads, and across every web, according to the company, and it also shows up in feeds in your google profile, which is required to use this products.