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
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.
idea.informer - Idea Informer is a idea forum similar to uservoice or getsatisfaction.
Kampsite - Start building features your users actually want.
All Our Ideas - All Our Ideas is a platform that enables groups to collect and prioritize ideas in a transparent, democratic, and bottom-up way. It’s a suggestion box for the digital age.