I think the deciding factor is how indiscriminate the question is. If I were to ask "Please suggest a good first-person shooter", that would be little more than a poll. Very indiscriminate. But if I were to ask, say, "Can you suggest a good adventure game for my 7-year old that I might also enjoy playing with him," that is very specific and not really a poll at all, even thought it may have several "correct" answers.
That's the distinction I believe these sites should consider when promoting what types of questions they want on the site.
I draw the distinction much more thoroughly in this [link to closed beta removed].
Oops, sorry. Link (above) is in closed beta. A bit unusual but I will quote the text directly here. The context is obvious enough.
From meta.cooking.SE:
Are Restaurant Mimicry Questions Allowed?
I'll take the opportunity of your question to re-assert the intention of my suggested moratorium on "recipe swap" questions. Hopefully people will link here for reference.
Are Recipe Requests Veiled, Indiscriminate Polls?
It was never my intention to suggest that recipes could never be discussed nor even mentioned on this site. However, I am trying to avoid the situation where the site fills up with lazy "I need a recipe for X" questions. But there is an important distinction between an indiscriminate recipe request (bad) and a recipe-related question (good).
Indiscriminate might be the distinction. "I need a recipe for X" is an indiscriminate question, asked without care nor making any distinction of why you are even bothering to ask experts. The answers aren't a product of expertise. It's barely a "real" question all. To me, it's akin to the shopping advice questions, banned on most sites.
Are restaurant mimicry questions allowed?
This question straddles right on the very edge of the on-topic side of the distinction I am trying to describe (above).
Someone can ask "What is the recipe for Red Lobster's biscuits?" (forget for a moment that no one knows the correct answer. irrelevant). But what they really should be asking is what makes them taste exactly that way. It's not an indiscriminate question when the criteria is so specific. The answer is very specific and, possibly, educational. As a recipe request, it's a poorly worded question. I would rather see it asked as "How do I get my biscuits to take more like Red Lobster's?" But that's a weird semantic argument that I hope people can see through. The important distinction is, are the answers going to be the work of someone's expertise in that area, or are the answers just the product of an indiscriminate shout-out poll?
The Caveat of a Moratorium
The danger of my suggested "moratorium on recipe requests" is that the mere mention or inclusions of a recipe in the post will trigger a knee-jerk reaction to shut down good questions. Recipes are the "language" of cooking and cannot be avoided. There's no recipes-are-a-dirty-word filter on this system. That's not my intention at all. To those people who are looking for that absolute true/false formula where you simply plug in a question and it comes out the other side happy... or it doesn't: Don't fall into that trap. Consider the context and the bigger picture.