Mathematics
Q&A for people studying math at any level and professionals in related fields
Stack Overflow
Q&A for professional and enthusiast programmers
Computational Science
Q&A for scientists using computers to solve scientific problems
Role-playing Games
Q&A for gamemasters and players of tabletop, paper-and-pencil role-playing games
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Physics
Q&A for active researchers, academics and students of physics
Biology
Q&A for biology researchers, academics, and students
Mathematica
Q&A for users of Wolfram Mathematica
MathOverflow
Q&A for professional mathematicians
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Game Development
Q&A for professional and independent game developers
Personal Finance & Money
Q&A for people who want to be financially literate
Computer Science
Q&A for students, researchers and practitioners of computer science
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Super User
Q&A for computer enthusiasts and power users
Board & Card Games
Q&A for people who like playing board games, designing board games or modifying the rules of existing board games
Space Exploration
Q&A for spacecraft operators, scientists, engineers, and enthusiasts
Code Review
Q&A for peer programmer code reviews
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
Signal Processing
Q&A for practitioners of the art and science of signal, image and video processing
Writing
Q&A for the craft of professional writing, including fiction, non-fiction, technical, scholarly, and commercial writing
Linguistics
Q&A for professional linguists and others with an interest in linguistic research and theory
Academia
Q&A for academics and those enrolled in higher education
Aviation
Q&A for aircraft pilots, mechanics, and enthusiasts
Software Recommendations
Q&A for people seeking specific software recommendations
Woodworking
Q&A for professional and amateur woodworkers