At the question-answering conferences I used to attend, the subject of question selection would always get short shrift: we don't know what kinds of questions people ask, so we will just construct our own set of questions and see how well various systems can answer them.
Google Suggest provides insight into actual questions that Google users have asked. Not sure how Google Suggest makes its suggestions, but presumably they are based on frequency (and the absence of bad words).
As such, it is interesting to see that, for example:
Can Jesus microwave a burrito?
Is a popular question? (My question: why would anyone ask "Can Jesus microwave a burrito?").
As always, users are infinitely more strange than systems engineers can imagine.
The examples here are well worth checking out.

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