Well, the key feature of a financial bubble is that no one is behaving irrationally at a micro level. Even if you know its a bubble, it may be worth trying to get in now and get out closer to the top.

Same thing with building social local mobile stain removal advice apps -- if someone's buying, then someone will be supplying it.

If it is really, no shit, a bubble, then there is a lot of money to be made by determining how to pop it.