Stack Overflow
Q&A for professional and enthusiast programmers
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Gardening & Landscaping
Q&A for gardeners and landscapers
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Travel
Q&A for road warriors and seasoned travelers
Ask Ubuntu
Q&A for Ubuntu users and developers
Arqade
Q&A for passionate videogamers on all platforms
Chemistry
Q&A for scientists, academics, teachers, and students in the field of chemistry
Information Security
Q&A for information security professionals
Graphic Design
Q&A for Graphic Design professionals, students, and enthusiasts
Academia
Q&A for academics and those enrolled in higher education
Motor Vehicle Maintenance & Repair
Q&A for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles
Vi and Vim
Q&A for people using the vi and Vim families of text editors
Seasoned Advice
Q&A for professional and amateur chefs
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Physics
Q&A for active researchers, academics and students of physics
Game Development
Q&A for professional and independent game developers
Software Quality Assurance & Testing
Q&A for software quality control experts, automation engineers, and software testers
Personal Finance & Money
Q&A for people who want to be financially literate
Server Fault
Q&A for 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
Aviation
Q&A for aircraft pilots, mechanics, and enthusiasts
Cryptography
Q&A for software developers, mathematicians and others interested in cryptography
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
WordPress Development
Q&A for WordPress developers and administrators
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Tor
Q&A for researchers, developers, and users of Tor
Video Production
Q&A for engineers, producers, editors and enthusiasts spanning the fields of video and media creation
Computational Science
Q&A for scientists using computers to solve scientific problems
Skeptics
Q&A for scientific skepticism
Web Applications
Q&A for power users of web applications
The Workplace
Q&A for members of the workforce navigating the professional setting
Theoretical Computer Science
Q&A for theoretical computer scientists and researchers in related fields
MathOverflow
Q&A for professional mathematicians
User Experience
Q&A for user experience researchers and experts
Signal Processing
Q&A for practitioners of the art and science of signal, image and video processing
SharePoint
Q&A for SharePoint enthusiasts
Ask Different
Q&A for power users of Apple hardware and software
Software Recommendations
Q&A for people seeking specific software recommendations
Mathematica
Q&A for users of Wolfram Mathematica
Blender
Q&A for people who use Blender to create 3D graphics, animations, or games
Area 51
Q&A for proposing new sites in the Stack Exchange network