Stack Overflow
Q&A for professional and enthusiast programmers
Data Science
Q&A for Data science professionals, Machine Learning specialists, and those interested in learning more about the field
Super User
Q&A for computer enthusiasts and power users
Geographic Information Systems
Q&A for cartographers, geographers and GIS professionals
Computational Science
Q&A for scientists using computers to solve scientific problems
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Software Recommendations
Q&A for people seeking specific software recommendations
Travel
Q&A for road warriors and seasoned travelers
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Ask Ubuntu
Q&A for Ubuntu users and developers
Ask Different
Q&A for power users of Apple hardware and software
Artificial Intelligence
Q&A for people interested in conceptual questions about life and challenges in a world where "cognitive" functions can be mimicked in purely digital environment
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization