Facebook is a relatively simple machine that can be reduced to an empirical formula. I am SMOBOT, and I see the world in numbers. OK, not quite, but let’s have a crack at it.

The platform was intended for college students almost exclusively upon conception. Word-of-mouth spread across dorms clogged with students, each connected to the internet, and all in close, isolated proximity to one another. There was a need to connect, and the means by which to do it. Students would have a way to connect, communicate and show off their connections, which was an incentive for them to recruit others to join the Facebook network.

Having saturated the college scene, Facebook opened things up to high school students, each connected via mini networks at school. And as soon as the PC became a staple good, Facebook opened their doors to anybody with an email account.

Facebook recently ballooned because of it’s new invite feature. Users can now import ALL of their email contacts though the invite feature, thanks in large part to Facebook’s acquisition of Plaxo. It works with Gmail, Yahoo, Live, Hotmail, etc. Without this key feature, Facebook would not have been able to achieve such rapid growth and dominate the social media market this past year.

Email notifications keep people coming back for more. Facebook sets almost any type of notification they can come up with to “on.” That means, whenever someone tags a photo of you, comments after you, posts to your wall, um… likes “this” with a Facebook thumbs up, pokes you, etc, you get an email notification, which sucks you back in. But it doesn’t come across as spam for a couple reasons. These are user-generated notifications, actions committed by your friends, most of which are well-received, and you have the option of turning these notifications on or off. So these notifications are very effective retention mechanisms, perhaps even more so than RSS or an email subscription to a blog might be.

Co-endorsement with the big television media players and radio personalities has been another way Facebook’s growth continues to surge. Facebook Pages offer news channels, famous individuals and corporations a way to syndicate their content, and in return, Facebook gets an honorable mention as the subscription mechanism of choice. The “pages” feature is very robust and doesn’t come off as spam. Myspace failed to separate personal profiles from organizations, which is why their spam problem still exists.

Thus,

Facebook = [College]x[Email]+Tom-Spam/3.1415926