Mathematics
Q&A for people studying math at any level and professionals in related fields
Stack Overflow
Q&A for professional and enthusiast programmers
Physics
Q&A for active researchers, academics and students of physics
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Super User
Q&A for computer enthusiasts and power users
Philosophy
Q&A for those interested in the study of the fundamental nature of knowledge, reality, and existence
Biology
Q&A for biology researchers, academics, and students
WordPress Development
Q&A for WordPress developers and administrators
Personal Finance & Money
Q&A for people who want to be financially literate
The Workplace
Q&A for members of the workforce navigating the professional setting
Chemistry
Q&A for scientists, academics, teachers, and students in the field of chemistry
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
English Language Learners
Q&A for speakers of other languages learning English
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Earth Science
Q&A for those interested in the geology, meteorology, oceanography, and environmental sciences
Home Improvement
Q&A for contractors and serious DIYers
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
History
Q&A for historians and history buffs
Server Fault
Q&A for system and network administrators
Reverse Engineering
Q&A for researchers and developers who explore the principles of a system through analysis of its structure, function, and operation