If there's anything I hope to be, it's a student. StackOverflow appeals to me in the same way Slashdot once did: it's a constant stream of new terminology I can almost, but not quite, understand. As I acquire mastery in one area, a new item of interest begins inspiring questsions and further opportunities to learn.
The majority of questions that I answer, I look up the answers and learn the subject with the asker. This may make my information inexpert on occasion, but it means I always check my work for correctness and often provide references that I used to research.
Server Fault
Q&A for professional system and network administrators
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Programmers
Q&A for professional programmers interested in conceptual questions about software development
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
The Workplace
Q&A for members of the workforce navigating the professional setting
Programming Puzzles & Code Golf
Q&A for programming puzzle enthusiasts and code golfers
Physical Fitness
Q&A for physical fitness professionals, athletes, trainers, and those providing health-related needs
Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites