Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community
Canny - Canny helps you collect and organize feature requests to better understand customer needs and prioritize your roadmap.
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
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
RealEye - Online Research Platform with Webcam Eye-Tracking.
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.