There has been a lot of discussion about questions that do not get answered on MSE, but are not considered 'research level' on MO and thus get closed. The problem seems to be that certain questions are too easy for MO, but get lost on MSE between the hundreds of easy-to-answer questions. (Even if you stick to a single tag (algebraic geometry in my case), many questions are easy exercises.)
One could argue that the target audience of MO is primarily faculty, and that MSE seems to be used mostly by undergraduates (this is certainly the impression one gets by looking at the active questions on the main page). If this analysis is correct, could it be useful to create a new 'in between' SE page aimed mostly at graduate students and postdocs?
The advantage of such a website would be that it would constitute a single place where graduate students can post and answer questions; where no question is too hard; but where one can still filter out elementary questions so that the interesting ones stick to the front page. This might also encourage more of the senior MO members to engage with the not-quite-research-level questions.
Graduate school is a weird time, and the types of questions one asks and is capable of answering are a big step away from both undergraduate work and research-level mathematics.
Remark. The reason I post this question is that I think there is a real problem with intermediate level questions, experienced by many people. This is one suggestion for dealing with it, but really I want to stimulate discussion rather than propose a single solution.