Computer geek since 1976, Internet geek since 1988, World Wide Web and Perl geek since 1994. Recently adept in Ruby and dipping my toe in the mobile-development waters (iOS/Cocoa Touch and Android).
Stack Overflow
Q&A for professional and enthusiast programmers
Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
Ask Different
Q&A for power users of Apple hardware and software
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
User Experience
Q&A for user experience researchers and experts
Server Fault
Q&A for professional system and network administrators
Programmers
Q&A for professional programmers interested in conceptual questions about software development
Mathematics
Q&A for people studying math at any level and professionals in related fields
Theoretical Computer Science
Q&A for theoretical computer scientists and researchers in related fields
Mi Yodeya
Q&A for those who base their lives on Jewish law and tradition and anyone interested in learning more
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Programming Puzzles & Code Golf
Q&A for programming puzzle enthusiasts and code golfers
Cryptography
Q&A for software developers, mathematicians and others interested in cryptography
Board & Card Games
Q&A for people who like playing board games, designing board games or modifying the rules of existing board games
Software Quality Assurance & Testing
Q&A for software quality control experts, automation engineers, and software testers