Earlier this year Google announced that they were now taking social media signals into consideration in their ranking algorithm, so now the ‘number of Tweets’ will play a part in how your website is ranked on Google. There is also a correlation between Facebook likes and high rankings although Google doesn’t directly use this data.
If you haven’t already heard, Google have recently released their +1 button. The idea is pretty simple and works in a similar way to the ‘like’ button on Facebook. It is a way of letting other Google users know what you think is cool, interesting or helpful.