I am a mathematician by profession and quite a long-time (since around 1995 – as of now , this means more than half of my life) TeX user by hobby.
I started with plain TeX, and much later (in the early 2000s) moved to LaTeX; I still use plain TeX occasionally (and when writing LaTeX classes/packages). Quite recently I also started to use ConTeXt.
I am a heavy Emacs user, though still a newbie – I started in 2001.
I have a blog about (among others) TeX and friends, located at http://mbork.pl/Content_AND_Presentation.
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Q&A for those involved in the field of teaching mathematics
Q&A for for those using, extending or developing emacs
Q&A for users of Mathematica
Q&A for professional and enthusiast programmers
Q&A for Ubuntu users and developers
Q&A for people who like playing board games, designing board games or modifying the rules of existing board games
Q&A for computer enthusiasts and power users
Q&A for professional mathematicians
Q&A for linguists, etymologists, and serious English language enthusiasts
Q&A for people studying math at any level and professionals in related fields
Q&A for committed Christians, experts in Christianity and those interested in learning more
Q&A for academics and those enrolled in higher education
Q&A for peer programmer code reviews
Stack Exchange Network staging zone, where users come together to build new Q&A sites