Shapado!

Stack Exchange is a fast-growing network of 84 [and counting] question and answer sites on diverse topics from software programming to cooking to photography and gaming. We are an expert knowledge exchange: a place where physics researchers can ask each other about quantum entanglement, computer programmers can ask about JavaScript date formats, and photographers can share knowledge about taking great pictures in the snow.

Super User, part of Stack Exchange , is a Q&A site for computer enthusiasts that's free. Free to ask questions, free to answer questions, free to read, free to index, built with plain old HTML, no fake rot13 text on the home page, no scammy google-cloaking tactics, no salespeople, no JavaScript windows dropping down in front of the answer asking for $12.95 to go away. You can register if you want to collect karma and win valuable flair that will appear next to your name, but otherwise, it's just free. And fast. Very, very fast. »

A Q&A site helps an online community to share knowledge. No matter what your area of interest, people with questions can get super answers fast. Question2Answer is a popular Q&A solution.

Server Fault is a Q&A site for system administrators and IT professionals that's free. Free to ask questions, free to answer questions, free to read, free to index, built with plain old HTML, no fake rot13 text on the home page, no scammy google-cloaking tactics, no salespeople, no JavaScript windows dropping down in front of the answer asking for $12.95 to go away. You can register if you want to collect karma and win valuable flair that will appear next to your name, but otherwise, it's just free. And fast. Very, very fast. »

OSQA is the free, open source Q&A system you've been waiting for. Your OSQA site is more than just an FAQ page, it is a full-featured Q&A community. Users earn points and badges for useful participation, and everyone in the community wins.

Solace is a fully open-sourced multilingual support and knowledge exchange platform written in Python.

Coordino allows you to create a question and answer system for you and your users to enjoy.

The MissionOur patented knowledge-sharing process, combined with the advantages of the Internet, allow us to change the way people solve their technology problems, gather information and share knowledge. The Experts Exchange Team is united in one vision: building the worlds best collaboration and knowledge-sharing solutions.HistorySince 1996, Experts Exchange has pioneered collaboration and knowledge sharing. Over 3,857,959 IT professionals from fortune 1000 companies from nearly every country in the world have signed up and used Experts Exchange as a way to solve their technical problems. Over 253,291 expert members have collaborated to create a searchable knowledge base of over 16,224,282 postings of previously answered questions. In 2000, Experts Exchange was awarded a patent for its knowledge sharing process. Experts Exchange has partnered with category leaders such as Oracle, Merrill Lynch, Zend, Research In Motion, Altavista, Network World, and many others.Welcome to Experts ExchangeExperts-Exchange.com is an IT and computer solutions community of more than 50,000 experts dedicated to exchanging knowledge and solving your technical problems. Experts Exchange is the most efficient and reliable IT resource on the Internet as evident by more than 2.6 million tech solutions. »

Askalot is a next generation CQA (Community Question and Answer) system.

BitAsker is a paid question and answer plateform using Bitcoin ... a user can win money by answering a question.