It's inevitable, though. Eventually the butcher's bill comes due; irrational valuations based on user growth or revenue alone always had a fuse attached to them, because they required a greater fool to come along and pick up the tab. Now that the tech market is having to mature and focus on profitability in general, VCs who only paid attention to the next big hype wave are going to get wiped out. Arguably, it would have been healthier if this had happened five years ago -- delaying the pain only increases it.