Answer Garden – It’s free online feedback system.
NO need any registration, You just type your question then done. BUT, you can leave your personal email to take a role of administrator. That is, you can get more control on your question.
The most disadvantages is : do not support Chinese Characters!
Application for Education:
I think it is better use as “Brain storm” or kind of “tag cloud” activities. Students can type unlimited ideas into the systems.
Some Concepts Some Ideas 