Stack Overflow
Q&A for professional and enthusiast programmers
Space Exploration
Q&A for spacecraft operators, scientists, engineers, and enthusiasts
Artificial Intelligence
Q&A for people interested in conceptual questions about life and challenges in a world where "cognitive" functions can be mimicked in purely digital environment
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Super User
Q&A for computer enthusiasts and power users
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Physics
Q&A for active researchers, academics and students of physics
Puzzling
Q&A for those who create, solve, and study puzzles
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
Academia
Q&A for academics and those enrolled in higher education
Information Security
Q&A for information security professionals
Code Review
Q&A for peer programmer code reviews
Server Fault
Q&A for system and network administrators
Game Development
Q&A for professional and independent game developers