The main website is Stackoverflow.com, is a blessing for professional and enthusiast programmers. It is not just a place where you go to solve a programming problem, it is a FEELING that you belong to the smart world. To that part of the world that has the curiosity to solve problems and the pleasure to help without being applauded for it.
List of Stackoverflow Communities
ASK Ubuntu
Ubuntu is a distribution of LINUX operating system. ASK Ubuntu is a great forum and a community for Ubuntu users and developers to get and provide help.
WordPress Development
WordPress is the most popular content management system (CMS). WordPress Development is a stackoverflow community for WordPress developers and administrators.
Android Enthusiasts
Android Enthusiasts is a forum for enthusiasts and power users of the Android operating system.
Artificial Intelligence
If you are interested in conceptual questions about life and challenges in a world where "cognitive" functions can be mimicked in purely digital environment, then Artificial Intelligence community is for you.
Arts & Crafts
Arts & Crafts is a forum for all the artists and painters for their problems and discussions about crafts.
Writing Beta
Writing Beta, professional writers who do about fiction, non-fiction, technical, scholarly, and commercial writing should use this forum.
Astronomy
I have never seen any online forum as good as Astronomy stack exchange community for astronomers and astrophysicists.
Bicycles
For people who build and repair bicycles, people who train cycling, or commute on Bicycles.
Bitcoins
For Bitcoins crypto-currency enthusiasts.
Anime and Manga
Community for Anime and Manga fans from around the web.
Also Read: Stackoveflow is a Huge Blessing For The World
Web Applications
Power users of Web Applications should join this community.
Windows Phone
Windows Phone enthusiasts and power users must seek help from this community.
Biology
Want to discuss Biology? There is a forum on stack exchange for biology researchers, academics, and students. Check it out!
Chemistry
Scientists, academics, teachers, and students in the field of chemistry can use this amazing forum.
Chinese Language
China is a growing and one of the largest markets of the world. We must learn their language to work with them, and most Chinese people only speak their local language. For any help with Chinese Language use this forum.