What exactly was the dot com bubble?

A bubble implies something that was over-inflated. You have rating systems in the stock market. Morningstar, I think may be one. People rely on these to know whether it is a good buy. Should I invest (buy) this stock? Stocks are not like a car where you can kick the tires etc. There are some common sense issues, but mostly it's amtter of ratings and a personal faith. Stocks are about the future which none of us can see. What happened was I imagine stocks were being reported as great investments( will pay out big money in the FUTURE), but in reality turned out to be the story of the Emperor's New Clothes. Nothing there. So you just handed a wad of cash over for nothing and the smart, clever people knew that this was phony and withdrew all their shares before the others did. Sort of like musical chairs. When the music ends you better have a chair or you'll be in the floor. Alot of people weren't anticipating the music to end so quickly(THE FUTURE being THEN) because of the positive ratings they thought the value would KEEP climbing over time.