It can be an incredible research tool as well. For example, you can calculate cost-of-living differences between different cities, or compare crime rates, or see how your SAT score compares to the national average.

The examples pages are rich (there are visual examples too), but would really benefit from some deep mashup-like examples. Wolfram|Alpha is really cool but I don't personally have much of a use for it; I'd like to be able to browse through it like Wikipedia.

How would I know what it can do without spending enormous amounts of time going through the examples?

Well, you wouldn't. I agree that there is a barrier to acceptance because it's hard to realize the full potential.

Powerful tools require a significant investment in time. It takes longer to learn how to use a lathe compared to say a hammer.

The problem is that what Wolfram Alpha can do beyond mathematics is rather arbitrary.