Programmers
Q&A for professional programmers interested in conceptual questions about software development
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
Stack Overflow
Q&A for professional and enthusiast programmers
Programming Puzzles & Code Golf
Q&A for programming puzzle enthusiasts and code golfers
Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
Server Fault
Q&A for professional system and network administrators
Photography
Q&A for professional, enthusiast and amateur photographers
Mathematics
Q&A for people studying math at any level and professionals in related fields
Audio-Video Production
Q&A for engineers, producers, editors, and enthusiasts spanning the fields of audio, video, and media creation
Physics
Q&A for active researchers, academics and students of physics
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Game Development
Q&A for professional and independent game developers
Graphic Design
Q&A for professional graphic designers and non-designers trying to do their own graphic design
Personal Productivity
Q&A for people wanting to improve their personal productivity
Board & Card Games
Q&A for people who like playing board games, designing board games or modifying the rules of existing board games
Software Quality Assurance & Testing
Q&A for software quality control experts, automation engineers, and software testers
LEGO® Answers
Q&A for LEGO® and building block enthusiasts