I'd argue that Facebook does not solve the problem and is just one of many solutions. As always with first new market exploiters their limitations will be featu

I'd argue that Facebook does not solve the problem and is just one of many solutions. As always with first new market exploiters their limitations will be features on newer, smaller, and more agile 2nd generation exploiters. You won't see a demise, or a new facebook rise up somewhere else, it will simply be subjected to fragmentation of the market.