Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
Personal Productivity
Q&A for people wanting to improve their personal productivity
Mathematics
Q&A for people studying math at any level and professionals in related fields
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
Server Fault
Q&A for professional system and network administrators
Stack Overflow
Q&A for professional and enthusiast programmers
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
Role-playing Games
Q&A for gamemasters and players of tabletop, paper-and-pencil role-playing games
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Cross Validated
Q&A for statisticians, data analysts, data miners and data visualization experts
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Programmers
Q&A for professional programmers interested in conceptual questions about software development
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
User Experience
Q&A for user experience researchers and experts
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Theoretical Computer Science
Q&A for theoretical computer scientists and researchers in related fields
The Workplace
Q&A for members of the workforce navigating the professional setting
Sports
Q&A for participants in team and individual sport activities
Programming Puzzles & Code Golf
Q&A for programming puzzle enthusiasts and code golfers
Cryptography
Q&A for software developers, mathematicians and others interested in cryptography
Martial Arts
Q&A for students and teachers of all martial arts
Computational Science
Q&A for scientists using computers to solve scientific problems
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