A large number of the popular social media sites out there these days will allow you to link to your websites within your personal profile. Sites such as LinkedIn (http://www.linkedin.com) offer this option and also provide links which have not been tagged with the No Follow attribute. meaning the links you place will pass link juice on to your page. Leveraging these social media properties in your favour while link building can be a strong tactic.
There are other social media websites available offering profiles however, and the same strategy may be applied to them also. Consider other options like Digg, Technorati, Mixx, or Kirsty, among others. Here are a couple larger lists of social media sites you may work within your link building strategies.
The policies each site has regarding No Follow are subject to frequent change. It is a good idea to check ahead and see what their current status is before investing too much time into building links on them.
Another popular choice for building links with social media is done via commenting. Find pages relevant to your content and leave thoughtful comments on the subject matter while referring to your own pages as a reference. I will say only fools spam blogs! Spamming blogs in the short term may bring rapid results but in the long term may well damage your site.
Start by Compile an extensive list of quality blogs which focus on subjects related to your own content. Once you have a quality list of blogs with potential start leaving quality and informative comments on a regular basis, without linking back to your website. Developing a relationship with the publisher via your comments, will go a long ways to ensuring your comments stay up, and will pass trust on to your future comments with other readers. The first steps to this relationship can be signalled when the publishers begins responding to your comments.
This tactic is meant to be applied conservatively with comments that compliment the original post. Simply spamming posts may well result in you being blacklisted from the site plus could even result in severe penalties from search engines if the webmaster chooses to report you.