Today, at Capital IT (see my previous post), Marc Simoncini from Meetic has pointed out that social networks were expensive (and long) to build while their business model (advertising and/or subscription) was unclear. Marc was talking about Friendster, Friendset, Orkut, etc. I think Marc is right. I have never understood how VCs could input so much money for these new "communities" concept (remember French Multimania?).
Let's think about it : you usually build a "social network" around common interests (say landscape photography) or for a dedicated goal with people you know (say your birthday party photo sharing). Would I have any interest to build a community with friends I already know. The answer is yes if I consider a particular topic as the core of our social ties (say tennis). Otherwise, I am afraid not.
Nevertheless, social networks with professional objectives (see LinkedIn) could be more valuable because I clearly see the added value for the end-user : sales, partnership, job search, etc.
I will follow carrefully what's going on social networks and business networks.