What is the difference between all the different types of bike?

m l asked: I.e. The difference between a spinning bike, a racing bike, a mountain bike, a road bike, and a hybrid, and any other types?

How is a regular exercise bike different than a spinning bike?

Kimmy asked: The buzz lately is that you can burn about 500 calories, tone up and lose weight quickly by exercising for only 30 minutes on a spinning bike.

I have a regular exercise bike and cannot afford a spinning bike or classes. Would I be able to achieve the same results by [...]