The Answer Bank - The Answer Bank is the UK’s leading question-and-answer site.
Question2Answer - A Q&A site helps an online community to share knowledge.
AnswersLOG - AnswersLog is a question-answer platform that provides unique features to help you to give answers to your questions in better ways and make your content more popular.
Stack Overflow - Community-based Q&A part of the Stack Exchange platform.
Ask Me Help Desk - Ask Me Help Desk is a question-and-answer site.
Blurtit - Blurtit is a Q&A website. You can ask a question or answer on any question.