Geographic Information Systems
Q&A for cartographers, geographers and GIS professionals
Stack Overflow
Q&A for professional and enthusiast programmers
Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
French Language & Usage
Q&A for students, teachers, and linguists wanting to discuss the finer points of the French language
Mathematics
Q&A for people studying math at any level and professionals in related fields
Physics
Q&A for active researchers, academics and students of physics
Web Applications
Q&A for power users of web applications
Theoretical Computer Science
Q&A for theoretical computer scientists and researchers in related fields
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Server Fault
Q&A for professional system and network administrators
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Cross Validated
Q&A for statisticians, data analysts, data miners and data visualization experts
Programmers
Q&A for professional programmers interested in conceptual questions about software development
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Graphic Design
Q&A for professional graphic designers and non-designers trying to do their own graphic design
Sustainable Living
Q&A for folks dedicated to a lifestyle that can be maintained indefinitely without depleting available resources