Cross marketing your social media ranks you highly in the organic rankings. Promote your social media pages and encourage people to join using the "follow me on ..." words and free social media icons like the one to the left. 

It is important to at least do this on your website and in your email signatures so people can hyperlink immediately through to your Facebook Wall, LinkedIn, Twitter, YouTube etc accounts. If you click on the Facebook icon above you will land on Marketing Talk's Facebook Wall - why not leave a post while you are there!