UserReport - Free online usability surveys with demographic information. Detailed click tracking for websites and feedback button for online user forum. Easy signup.

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

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.

Survey Monkey - Create and publish online surveys in minutes, and view results graphically and in real time. SurveyMonkey provides free online questionnaire and survey software.

Zendesk - Zendesk is a beautiful, lightweight help-desk solution.

Canny - Canny helps you collect and organize feature requests to better understand customer needs and prioritize your roadmap.