Okay, now, this was slightly difficult to title, but let me explain.
Sometimes, if you see a question, it may not actually be a problem, but more so asking about features etc. Now, 90% of the time people are asking for teh codez or a third party library to do their bidding.
However, some questions that aren't about a problem, can become some of the most popular questions on the site.
Case in point: Hidden Features of C#?
The above question is incredibly useful. In fact, it's probably my favourite one on StackOverflow. Now, it's been closed as not constructive, but my question is, why isn't it?
Not constructive states:
We expect answers to be supported by facts, references, or specific expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, see the FAQ for guidance.
These are facts, they're features of the language that are not widely known. They're supported by references, there's no debates/arguments in that question. So why close it?
I think questions like these (and you can see by the views and votes) will bring a lot of traffic into StackOverflow, why should we Close them?