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
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 is the most popular content management system (CMS). WordPress Development is a stackoverflow community for WordPress developers and administrators.
Android Enthusiasts is a forum for enthusiasts and power users of the Android operating system.
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, professional writers who do about fiction, non-fiction, technical, scholarly, and commercial writing should use this forum.
I have never seen any online forum as good as Astronomy stack exchange community for astronomers and astrophysicists.
For people who build and repair bicycles, people who train cycling, or commute on Bicycles.
For Bitcoins crypto-currency enthusiasts.
Anime and Manga
Community for Anime and Manga fans from around the web.
Power users of Web Applications should join this community.
Windows Phone enthusiasts and power users must seek help from this community.
Want to discuss Biology? There is a forum on stack exchange for biology researchers, academics, and students. Check it out!
Scientists, academics, teachers, and students in the field of chemistry can use this amazing forum.
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.