The dot com bubble was based on hype, but the premise behind that hype was legitimate. At $38 per monthly site visitor (the average for recent deals) good site traffic is worth good money. I’ve recently started running ads on some sites of mine that have very little traffic, but I’m amazed at the little money I make of them. Once traffic grows exponentially, which it does, decent traffic can explode into great traffic, which equals healthy ad revenues.
Here’s a great article on monetizing web traffic: High Traffic Monetization [Business 2.0]