LeonardSipes.Com
See the link below from YouTube regarding a wonderful video on social media. If you have to explain or justify the concept to others, this will do it.
See http://www.youtube.com/watch?v=lFZ0z5Fm-Ng
Also see the link to Common Craft videos on the right side of this site. While not nearly as dramatic as the one linked here, they do an excellent job explaining unique aspects of social media.
Enjoy.