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.

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.

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

FEEDBACKdeck - FEEDBACKdeck brings to WordPress, a gorgeous way to capture user feedback.

Survicate - Collect feedback on your website and find out more about your visitors.

UserEcho - UserEcho gives you the opportunity to create a modern Community to support customers in a few minutes. It includes support forum with the possibility of voting for ideas, Helpdesk, Knowledge Base and Online Chat.