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Christianity
Q&A for committed Christians, experts in Christianity and those interested in learning more
Biblical Hermeneutics
Q&A for professors, theologians, and those interested in exegetical analysis of biblical texts
Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
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.
Mi Yodeya
Q&A for those who base their lives on Jewish law and tradition and anyone interested in learning more
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
Academia
Q&A for academics and those enrolled in higher education
Musical Practice & Performance
Q&A for musicians, students, and enthusiasts
Server Fault
Q&A for professional system and network administrators
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Mathematics
Q&A for people studying math at any level and professionals in related fields
Geographic Information Systems
Q&A for cartographers, geographers and GIS professionals
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Stack Apps
Q&A for apps, scripts, and development with the Stack Exchange API
Motor Vehicle Maintenance & Repair
Q&A for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles
Islam
Q&A for Muslims, experts in Islam, and those interested in learning more about Islam