Mathematics
Q&A for people studying math at any level and professionals in related fields
Ask Different
Q&A for power users of Apple hardware and software
Bitcoin
Q&A for Bitcoin users, developers, and enthusiasts
Area 51
Q&A for proposing new sites in the Stack Exchange network
Information Security
Q&A for information security professionals
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Philosophy
Q&A for those interested in the study of the fundamental nature of knowledge, reality, and existence
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Tor
Q&A for researchers, developers, and users of Tor
Academia
Q&A for academics and those enrolled in higher education
Server Fault
Q&A for system and network administrators
Web Applications
Q&A for power users of web applications
Cryptography
Q&A for software developers, mathematicians and others interested in cryptography
Seasoned Advice
Q&A for professional and amateur chefs
Skeptics
Q&A for scientific skepticism
Stack Overflow
Q&A for professional and enthusiast programmers
Personal Finance & Money
Q&A for people who want to be financially literate
Ask Ubuntu
Q&A for Ubuntu users and developers
Video Production
Q&A for engineers, producers, editors and enthusiasts spanning the fields of video and media creation
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
History
Q&A for historians and history buffs
Super User
Q&A for computer enthusiasts and power users
German Language
Q&A for speakers of German wanting to discuss the finer points of the language and translation
Poker
Q&A for serious players and enthusiasts of poker
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Japanese Language
Q&A for students, teachers, and linguists wanting to discuss the finer points of the Japanese language