Social Networks require "stalkers"

Okay okay, not quite...but read on for my explanation.

Sign up for any social network, be it Facebook, Twitter, or MySpace (among the many others), and you have the option to search for existing friends. Most people know at least one other person using a particular network so they always have a friend. Some just create an account because it's there.
For a social network to be truly successful, some of the users need to search out others. If everyone just creates an account and sits there waiting, no connections could possibly be made! The people who spend a few hours looking through people from their high school or college, for example, end up making new connections. As an added bonus, those new connections may spark other users to find each-other as well!
I say it jokingly, but the "stalkers" are the ones spinning the social web of many of these networks. When you think to yourself, "Hmm. I wonder if anyone I work with has a Facebook profile.", that becomes the catalyst for a new connection. Maybe it even inspires a conversation in the faculty lounge, sparking interest and curiosity, leading to more faculty creating profiles. Then, the students (most of which, probably already have profiles!) will be searching, and link up. NOW, we can start using social networks in education in addition to for education!
From there, the possibilities are infinite.