People make use of social media marketing, SMM, for different reasons.  It could be that your goal is to get rid of negative links out of the top 10 or 20 results of off search engines.  It could also be for the reason of getting the desired backlinks.  Most often than not, though, the reason is to gain visibility.  Once you have established your reputation or profile as a site that has credibility and value, your site will become sought after by people.  This creates power in such a way as to persuade people into believing in your ideas or goals.  What you have to say will then have greater weight.

There are many different social marketing sites that are worth looking into when planning for your social marketing campaign.  A brief list of them are the following: Digg, Del.icio.us, Wikipedia, Flickr, Reddit, Newsvine, StumbleUpon, Technorati, MySpace, Yahoo! Answers, and many more.