English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Stack Overflow
Q&A for professional and enthusiast programmers
German Language & Usage
Q&A for speakers of German wanting to discuss the finer points of the language and translation
Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
Russian Language & Usage
Q&A for students, teachers, and linguists wanting to discuss the finer points of the Russian language
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Physics
Q&A for active researchers, academics and students of physics
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Server Fault
Q&A for professional system and network administrators
Mathematics
Q&A for people studying math at any level and professionals in related fields
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Photography
Q&A for professional, enthusiast and amateur photographers
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.
Motor Vehicle Maintenance & Repair
Q&A for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles
Cognitive Sciences
Q&A for practitioners, researchers, and students in cognitive science, psychology, neuroscience, and psychiatry
Personal Finance & Money
Q&A for people who want to be financially literate
Linguistics
Q&A for professional linguists and others with an interest in linguistic research and theory
Writers
Q&A for authors, editors, reviewers, professional writers, and aspiring writers
Physical Fitness
Q&A for physical fitness professionals, athletes, trainers, and those providing health-related needs