The new button, dubbed “+1”, will appear next to search results and advertisements on Google.
A +1 click can be shared with users’ friends on their Google Account and any links recommended by friends will appear higher in search results.
The data from clicks will also be added anonymously to public data, which Google will use – among other signals – to calculate pages’ relevance and ranking on search results.
In a blog post, Google says advertisers will not have to adjust their Adwords strategy because the way it calculates its quality score will not change.
The +1 button will launch across English searches on Google.com but it will roll out across more languages in the future.
Google says it will also expand the use of +1 for websites to integrate the button on their own pages as well as in search results.
The search engine giant’s move into social search comes on the same day it agreed to settle a complaint from the Federal Trade Commission over privacy violations on its previous social networking effort Google Buzz.