CiviCRM
Q&A for administrators and users of the CiviCRM Constituent Relationship Management software
Graphic Design
Q&A for Graphic Design professionals, students, and enthusiasts
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Mathematica
Q&A for users of Wolfram Mathematica
Super User
Q&A for computer enthusiasts and power users
Software Recommendations
Q&A for people seeking specific software recommendations
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Server Fault
Q&A for system and network administrators
Stack Overflow
Q&A for professional and enthusiast programmers
Photography
Q&A for professional, enthusiast and amateur photographers
Area 51
Q&A for proposing new sites in the Stack Exchange network
Woodworking
Q&A for professional and amateur woodworkers
Home Improvement
Q&A for contractors and serious DIYers
Ask Different
Q&A for power users of Apple hardware and software
Drupal Answers
Q&A for Drupal developers and administrators
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
Information Security
Q&A for information security professionals
Signal Processing
Q&A for practitioners of the art and science of signal, image and video processing
Geographic Information Systems
Q&A for cartographers, geographers and GIS professionals
Ask Ubuntu
Q&A for Ubuntu users and developers
Lifehacks
Q&A for people looking to bypass life's everyday problems with simple tricks
Sustainable Living
Q&A for folks dedicated to a lifestyle that can be maintained indefinitely without depleting available resources
Music: Practice & Theory
Q&A for musicians, students, and enthusiasts
Code Review
Q&A for peer programmer code reviews
Mathematics
Q&A for people studying math at any level and professionals in related fields
Web Applications
Q&A for power users of web applications