Several years ago when this site was launched there were quite a few discussions about what is or should be the scope of the site, see for example Scope of the site: educaTION versus educaTOR
Since quite some time has passed, it might be worthwhile to revisit the subject to see if there is need for clarification.
Not to make this discussion overly broad let us focus this discussion on the intended audience.
It seems clear that we want to cater to persons actively involved in teaching of mathematics1. But who else:
- parents (and equivalent) of children in school?
- persons generally interested in the subject?
This post might be a bit vague, but I hope it can still serve some purpose.
- What I meant to convey is that persons that are, or were, involved with mathematics education in a professional capacity, or something resembling this, in my mind are clearly part of the target audience. Joel's answer names some groups in that category that are not, or at not necessarily, actually teaching mathematics.