Networks have always been crucial to businesses and now they've moved online. Millions of people are now using sites like MySpace and Facebook. The demographic tends to be younger and entertainment focused for those sites, but there are also business focused sites like LinkedIn and Plaxo.
Online networks are able to leverage the breadth and reach of instant and asynchronous communication.
Are you part of an online social network? What could you gain by being a part? What could you give?