The worst part of it is, they think it won't happen "this time", that the bubble won't burst. That 30-100% year to year growth rates are sustainable. The only way you get that kind of growth is with a new tech or product, very early in its introduction, where the absolute numbers are small. It's much easier to go from selling 10 widgets to 20 widgets than from selling 1E6 widgest to 2E6 widgets, but both are 100% growth rates. These bubbles trap unwary investors, which are often people who bet the farm chasing the stock, commodity, etc. It just makes me wince to see how naive people can be. When the stupid mortgages came out a few years ago (zero down, low "teaser rates" etc.) I would rant at the TV screen, imploring people not to be suckers and fall for this!