We've put it in the FAQ, but there's still a lot of questions being asked that need location data and don't have it. I'd like to suggest that we ask the SE team to ask the user to state their location on the Ask A Question page itself.
As many people have figured out, it's incredibly important to state your location and give information about your climate, especially when you're considering changing the building envelope. The advice that I'd give regarding building envelope, insulation, penetrations of the envelope, and attic ventilation as a 2A/Hot-Humid Texan is completely different than the advice that's correct for someone living in British Columbia or even the US upper Midwest. As an example, in the US upper Midwest you would put insulation, and then a vapor barrier against the drywall. In the US deep South, putting up a vapor barrier like that would cause your drywall to rot.
Another example is that Maryland and Illinois have adopted the 2012 IECC, but all other US states are still on the 2009 code. Obviously, answers for people who are in Illinois or Maryland are going to be different.
Question askers don't necessarily know that the answer is going to depend on their region, so they don't think to state it. This has caused a lot of repeat questions, but unlike most people, I don't think that's a bad thing as long as the question is edited to make the location obvious. (That often falls on the mod team...) My main concern is that the question asker will do something completely unsuitable for their environment without knowing why or how. Answerers can't cover all the bases.