Can you make money (revenue) off social media sites like Facebook, Twitter, Instagram, etc? And if you can't, will social someday become a fad?

[youtube http://www.youtube.com/watch?v=VAcUyNdkYkU&w=620&h=315]

Let's start with a couple of basics: Facebook and Twitter, the two behemoths in the general social media space right now (I'd classify Instagram as Facebook, and I might include YouTube as the third behemoth), are now both public companies. As a result, they have evolving needs. As a result…