Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
Musical Practice & Performance
Q&A for musicians, students, and enthusiasts
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
Photography
Q&A for professional, enthusiast and amateur photographers
Graphic Design
Q&A for professional graphic designers and non-designers trying to do their own graphic design
Audio-Video Production
Q&A for engineers, producers, editors, and enthusiasts spanning the fields of audio, video, and media creation
WordPress Answers
Q&A for WordPress developers and administrators
Physics
Q&A for active researchers, academics and students of physics
Server Fault
Q&A for professional system and network administrators
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Cognitive Sciences
Q&A for practitioners, researchers, and students in cognitive science, psychology, neuroscience, and psychiatry
Answers OnStartups
Q&A for entrepreneurs looking to start or run a new business
The Workplace
Q&A for members of the workforce navigating the professional setting
Computer Science
Q&A for students, researchers and practitioners of computer science
Physical Fitness
Q&A for physical fitness professionals, athletes, trainers, and those providing health-related needs
Ask Different
Q&A for power users of Apple hardware and software
Programmers
Q&A for professional programmers interested in conceptual questions about software development