Mostly retired mathematician trying to help where I can: soft questions, elementary number theory, philosophy (differentials and infinitesimals), algebra newbies.
In TeX I tend to try to answer my own questions myself (often with ugly hacks!) so don't ask many here. As an answerer I'm better at do-it-outside-TeX and at helping newbies with easy questions than at competing with the wizards. I've used but never written a macro that needed \makeatletter.