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

Stack Overflow Trends - Current programming and technology trends by Stack Overflow

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.

Stack Overflow for Teams - Everything you love about Stack Overflow in a private space.

idea.informer - Idea Informer is a idea forum similar to uservoice or getsatisfaction.

Answer Bot by Intercom - Instant resolutions, happier customers