Stack Overflow
Q&A for professional and enthusiast programmers
Space Exploration
Q&A for spacecraft operators, scientists, engineers, and enthusiasts
Expatriates
Q&A for people living abroad on a long-term basis
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
User Experience
Q&A for user experience researchers and experts
Ask Different
Q&A for power users of Apple hardware and software
Ask Ubuntu
Q&A for Ubuntu users and developers
Web Applications
Q&A for power users of web applications
Photography
Q&A for professional, enthusiast and amateur photographers
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
The Workplace
Q&A for members of the workforce navigating the professional setting
Travel
Q&A for road warriors and seasoned travelers
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Server Fault
Q&A for system and network administrators
SharePoint
Q&A for SharePoint enthusiasts
Information Security
Q&A for information security professionals
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Super User
Q&A for computer enthusiasts and power users
History
Q&A for historians and history buffs
WordPress Development
Q&A for WordPress developers and administrators