I'm relatively new to Stack Exchange, so I'm not sure if there is a universal policy for closing questions across sites. But I've noticed here that there are questions with low or negative scores or questions that are similar to ones asked and answered before, and they're left hanging on the front page. Turnover seems slow compared to other SE sites.
I just wanted to put this out for discussion, I don't have a terribly strong opinion about it either way.
The main problem here is that there are far fewer moderators, so most posts don't reach the number of close votes necessary to close. The solution to this is (1) flag offending posts so that site-wide mods can vote to close, and (2) vote to close if you have the capability to do so.
I wanted to offer an alternative to @CharlesMorisset's answer.
Closing a question is not an end-all to a question. It is not deleting (which is almost never done). The OP can edit a question after it is closed, thus I think vague or very-weak questions should be proactively closed with a comment letting the user know that they should edit their question and request for re-open on meta.
Three reason I think we should close questions:
If a vague question is not closed, then someone might spend time trying to answer the question. After, the original question cannot be made unvague because it might render the original answer off-topic. I don't think we are in a slum for questions, but it is very easy to ask poor questions, and we should try to avoid those.
Asking bad questions is sometimes a chronic condition. In the beta period, a single user seeding with a lot of poor questions can really lower the quality of a site. I think there might have been issues with this in the early period of cogsci.SE. Closing a question sends a very clear message to the user that their question is not upto the standards of the site.
We are not starved for questions, and we have a lot of academics on the site who seem to be participating actively. However, I think this SE is particularly vulnerable to quick weak questions that can overwhelm the front page and make it hard to attract new users, or scare away existing expertise.
In other words: I think we have reasons for closing, and not many against it.
It's a good remark. In general, I think it can be good to leave the time for the OP to reformulate the question before closing, but there should be some kind of time limit. For instance, this question has been there for 4 days, and it is still quite vague.
Is there some kind of mechanisms to trigger a poll to close a question?
EDIT: After seeing Artem's answer, I realized that it was possible to reopen a question. In this case, I change my opinion, and think that indeed, it should be better to vote to close any poor quality question immediately, leave a comment, and see if the OP edit his/her question accordingly.
