Aviation
Q&A for aircraft pilots, mechanics, and enthusiasts
Space Exploration
Q&A for spacecraft operators, scientists, engineers, and enthusiasts
Physics
Q&A for active researchers, academics and students of physics
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Law
Q&A for legal professionals, students, and others with experience or interest in law
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Super User
Q&A for computer enthusiasts and power users
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Pets
Q&A for pet owners, caretakers, breeders, veterinarians, and trainers
Information Security
Q&A for information security professionals
Personal Finance & Money
Q&A for people who want to be financially literate
Stack Overflow
Q&A for professional and enthusiast programmers
Motor Vehicle Maintenance & Repair
Q&A for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles
Drones and Model Aircraft
Q&A for experienced flyers, pilots, and builders of drones and model aircraft
Arqade
Q&A for passionate videogamers on all platforms
Ask Different
Q&A for power users of Apple hardware and software
Mathematics
Q&A for people studying math at any level and professionals in related fields
Server Fault
Q&A for system and network administrators
Music: Practice & Theory
Q&A for musicians, students, and enthusiasts
Physical Fitness
Q&A for physical fitness professionals, athletes, trainers, and those providing health-related needs
Movies & TV
Q&A for movie and TV enthusiasts
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
Retrocomputing
Q&A for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear
Medical Sciences
Q&A for professionals in medical and allied health fields, students of those professions, related academics, and others with a sound understanding of medicine and healthcare-related sciences
Ask Ubuntu
Q&A for Ubuntu users and developers
English Language Learners
Q&A for speakers of other languages learning English
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Network Engineering
Q&A for network engineers
Astronomy
Q&A for astronomers and astrophysicists
Engineering
Q&A for professionals and students of engineering
Computer Science
Q&A for students, researchers and practitioners of computer science
Academia
Q&A for academics and those enrolled in higher education
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Chess
Q&A for serious players and enthusiasts of chess
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Home Improvement
Q&A for contractors and serious DIYers
The Great Outdoors
Q&A for people who love being outdoors enjoying nature and wilderness, and learning about the required skills and equipment
Cryptography
Q&A for software developers, mathematicians and others interested in cryptography