I wanted to raise this question based on the discussion here. An example would be "What are some real world applications for genetic algorithms?"
The decision here should be added into our FAQ.
There seems to be quite a bit of interest in answering some applied questions. (I've answered some myself.) After I commented that http://cstheory.stackexchange.com/questions/2050/approximation-algorithms-for-maxsat was off topic, Peter Shor replied:
Is there a consensus that heuristic algorithms for rigorously defined problems are on-topic, even if we can't prove anything about them? Should we distinguish methods with theoretical partial results (such as branch and bound, which is easily proven correct albeit potentially exponential) from methods with very little theory (such as genetic algorithms)?
Here's an example of an applied question that's not off topic:
Here's an example that is on the border:
Here's an example that is off topic: