We recently had a brief discussion in chat about this question which asks for learning materials (specifically, online video courses). I feel that such questions are not a good fit for the site because:
They are not about a problem. The SE network specializes in giving specific solutions to specific problems, this type of question is either "too broad" or "opinion based".
Any answers given will become obsolete very quickly as the courses change, links die, the institutions or individuals giving the courses update or change them etc etc. Answering this kind of question seems to invite link rot.
Now, I may be influenced in this by Super User where one of the close reasons is:
Questions seeking product, service, or learning material recommendations are off-topic because they tend to become obsolete quickly. Instead, describe your situation and the specific problem you're trying to solve. Here are a few suggestions on how to properly ask this type of question.
I feel we should allow questions requesting books which, as physical objects, are likely to stick around longer than random links to online resources. Requests for online learning material, on the other hand, are more problematic. Forget books as well, the same basic issue applies, there is no single authoritative answer, asking for books can very easily degenerate into a long list of references, making it very hard to choose one answer as the 'correct' one.
So, what do we feel about this here? Should we add the above to our list of close reasons?