Google and Bing confirmed that it is true that they use social signals from Facebook and Twitter in their search algorithms. This news was revealed to us all, through an article on an interview conducted by Danny Sullivan, editor-in-chief of Search Engine Land . The interview was titled 'What Social Signals Do Google & Bing Really Count?' and the confirmation news was revealed early this month.
On 20 December, a Google engineer, Matt Cutts, posted a new video on the Google Webmaster YouTube Channel that reconfirms Google's usage of social signals in their search algorithms. The posted video also revealed that till May 2010, Google did not use any social signals in their search algorithms. However, today they do. Matt explained that the social signals are mostly used in the real-time search index and that they are “studying” how to expand it more into other areas of search, including web search.
In addition, Matt also explained that merely having a large number of followers will not help in ranking well. You need to have followers with good reputation, meaning quality matters, and not just quantity. So if you get your page mentioned in tweets by authoritative people, it can help your ranking in regular search results, up to an extent. It is likely that social signals will gain even more weight in search ranking systems in future.