[anamax]

> If there is only one answer to one factual question, why not have it already written and available like wikipedia?

Wikipedia isn't all that useful for storing all of the sums of integers.

In other words, you can't enumerate all of the questions that have one answer.

[TweedHeads]

Google 2+2

Not to be a dickhead, I know what you mean.

Questions that involve some kind of processing power can be a good target for Wolfram, but then, how much marketable besides academia?

The answer to the population of X country/city/town = wikipedia, plus more facts you may be interested while doing your research paper.

Maybe I just need 10 different questions/implementations of such service to get it.

[logicalmind]

Couldn't you just do this:

askwolfram "What are all of the questions that will ever be asked?" | askwolfram "How do I format this answer for wikipedia?" > wikipedia.html