GetSatisfaction - Get Satisfaction is the leading customer engagement platform that helps companies build better relationships with their customers and prospects, through the best online customer community.

Stack Overflow - Community-based Q&A part of the Stack Exchange platform.

UseResponse - Open-source, self-hosted customer feedback software, live chat and helpdesk system that you can install on your server. Organize documentation using knowledge base and get feedback from social networks with centralized system

The Answer Bank - The Answer Bank is the UK’s leading question-and-answer site.

UserVoice - UserVoice integrates easy-to-use feedback, helpdesk, and knowledge base management tools in one platform that empowers users to speak and companies to understand.

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