This article was posted last year in September on http://www.insidermusicbusiness.com.  It provides a great diagram for social networking.  The focus is for musicians but its uses are unlimited.  Check out their Basic Multimedia Strategy.
Social Media Strategy For Musicians – Facebook, Myspace, YouTube & More | Insider Music Business.

 Do we have it easy today or what? I can’t help to think about the countless musicians that got started twelve or so years ago and did not have the technological tools we have today. I wonder about the countless bands that played regular gigs that never got noticed based on lack of album distribution. [...]