I often find myself considering implementing something new in my classroom, but wanting advice from more experienced teachers. Such questions are not really appropriate for Math.SE, since they solicit opinion (tagging them as "reference-request" is slightly dishonest and probably not what I want anyway). Are there other active communities for such questions? I've just today found The Mathematics Teaching Community, but I wonder if there are others.
I would like to recommend that people use the Mathematics Teaching Community site. It was developed by my colleague Sybilla Beckmann, with the assistance of my PhD student Jacob Hicks. I think it is a very nice site, with one notable flaw: only a tiny percentage of the mathematics teaching community knows about it, so only a tiny percentage is active there. More activity would really make it come alive.
At the same time, I would also be happy to see math education questions on this site. The idea that a site which is mainly populated by math researchers, math teachers and math students should regard math education as being off-topic seems a little loony to me, to be honest. (This seems to me to be related to the standard conceit of this site as part of the se system: that it is about answering math questions rather than teaching mathematics. As the years roll by I find this increasingly awkward: for the majority of the material asked here, it is almost a priori impossible that the person asking the question is not a student of mathematics asking it in the context of trying to learn mathematics.) Such questions here seem to meet a good or bad fate based on rather contingent requirements. For instance, questions like "How to deal with 'Will this be on the test?'" are regarded as off-topic because one could ask those questions of teachers in other subjects. Well, yes, but the answers will be different (or could be different, which amounts to the same thing).
Saying that such questions should go to academia.se or some future se site focusing on undergraduate education seems precisely to miss the point that Beckmann's site is predicated upon: it is natural to draw boundaries so as to regard all mathematics educators as a single community. This is both large enough to be productive -- it would be great if I had a clue about what K12 math teachers were doing, and vice versa -- and small enough to be productive: English or history or art teachers have their own communities and their own challenges. Although it is nice to sometimes participate in this larger community (and I have spent time on the Chronicle of Higher Education forum, for instance), almost invariably whenever I see someone in a different discipline answer a teaching question I think, "Interesting, now I wonder how it is in math?"
However, I do agree that the question and answer format often does not work so well for mathematics education questions, which tend to be more open-ended. So if one wants to start a discussion, using my colleague's website seems to be better than asking the question here.
In view of the feedback here, I created an Area 51 proposal. Please help it to succeed!
The StackExchange network currently has a beta site called Academia (This site is for academics of all levels—from aspiring graduate and professional students to senior researchers—as well as anyone in or interested in research-related or research-adjacent fields.), but it is only for graduate education and higher.
There are at least two proposed sites at Area 51, one is called Education (Proposed Q&A site for professional educators and education researchers, K-12 & higher ed teachers, vocational teachers, school administrators, school faculty, education psychologists, education historians, education theorists and philosophers, non-profit educationists) and the other is called Higher Education (Proposed Q&A site for questions related to higher education, high school, college and grad school admissions including preparation of standardized tests like GRE, SAT.), but neither one focuses on mathematics.
There used to be an Area 51 proposal for mathematics education, but it died.