Stack Overflow
Q&A for professional and enthusiast programmers
Super User
Q&A for computer enthusiasts and power users
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Web Applications
Q&A for power users of web applications
Server Fault
Q&A for system and network administrators
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Physics
Q&A for active researchers, academics and students of physics
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Personal Finance & Money
Q&A for people who want to be financially literate
Chemistry
Q&A for scientists, academics, teachers, and students in the field of chemistry
Mathematics
Q&A for people studying math at any level and professionals in related fields