Canny - Canny helps you collect and organize feature requests to better understand customer needs and prioritize your roadmap.
osTicket - osTicket is a widely-used open source support ticket system.
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
Zammad - The Zammad - Help Desk and Ticket System - Community Page
RealEye - Online Research Platform with Webcam Eye-Tracking.
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.