When any advertising-based startup can raise $50 million on a $1 billion market cap, there's not much market for new ideas. Why bother, when the same-old-stuff can make you rich.
2007: "Advertising will get more and more targeted until it disappears, because perfectly targeted advertising is just information."
But when the bubble fades, it's time to get creative. Because tech will reboot. The question is, what's the next wave.