We all know that Social media is the "next big thing." But have you considered how it affects SEO?
As you've probably heard Google is pulling in relevant Tweets into its index. That means that if you Tweet your keywords it's going to help your sites position in search, provided you also link the keyword to your site.
And of course Google has come out with +1 button, which seems to be a bit along the lines of the Facebook "like" button.
Although, until I actually see it working in the wild, and on my own site, I'm going to withold judgement.