I know, the issue of our policy on reference requests was discussed (too) many times:
b. The idea of a chat-room serving as a reference-desk: Praised but, aparently, abandoned; also a suggestion to send reference-requests to chat here; the idea of "select reference-lists" and a call for a CW references list; T.E.D.'s elaborate proposal; Mark C. Wallace's elaborate proposal: No idea what happened to these.
From what I understand, some limited reference requests are OK, but what about other proposals (such as selected lists, CW, chatroom): Did we try to implement these but it did not work?
I understand why we have a policy against general reference requests, but I do not feel good about just closing such questions: Where should people ask if not here? Answering in comments is not right either. Telling people to read Wikipedia articles is not right as well, since the number of references there can be overwhelming and most are irrelevant for a newbie.
Since, I assume, the other proposed ideas did not work, did we try channeling reference requests to Meta-HSE? Of course, Meta is not meant for this, but answering on Meta would resolve at least some issues related to reference requests (such as gaining reputation by posting trivial answers, or attracting low quality answers). Unlike chatrooms, Meta is easily searchable; Meta-votes mean something quite different from votes on main; Meta-questions need not admit definitive answers: disagreement on Meta is common (by design).
OK, now to the question of why am I reopening the old issue which was discussed at length before:
I am very hesitant reviving at once many old threads (primarily items in b and c lists), but curious to find out what (if anything) happened.
The meta-based proposal for reference lists appears to be new (but I might have easily missed something).
Lastly: It is quite possible that nothing can be done regarding reference requests since people most active on this site are too busy or/and tired of discussing this issue, or mostly are opposed to reference requests of any type. That would be a fine answer as well.
Edit. To answer mod's question asked in a comment to one of the answers:
1. I am active on three other stackexchange sites: Mathoverflow (MO), Math.stackexchange (MSE) and History of Science and Mathematics (HSM). All three allow for reference requests; to give few examples from HSM (since it is closer to HSE):
d. "Books on the History of Physics": I think this request was not shot down because the body of the question made it clear that the questioner was primarily interested in history of Quantum Mechanics.
e. But this reference request was too broad and closed for that reason:
2. Two more stack exchange sites I am familiar with (but not active at): matheducators and physics.
(i) Matheducators allow for very broadly-stated reference requests such as:
What are some great books for exploring mathematics? (not kids' books and not textbooks). It was well-received and had many answers.
(ii) The current situation on physics stack exchange is less clear, but they created (via CW) a large list of book references for variety of topics in physics, Book recommendations [closed], with the preamble:
Every once in a while, we get a question asking for a book or other educational reference on a particular topic at a particular level. This is a meta-question that collects all those links together. If you're looking for book recommendations, this is probably the place to start.
However, of course, each stackexchange site has its own culture regarding what questions are acceptable.
Edit. So far, looking at the votes, it appears that there is nothing close to a solid majority agreement on anything regarding references (the split is about 50-50). But maybe the sample is too small.