Critique Circle is a closed community of writers whose purpose is to allow authors to submit and receive feedback/constructive criticism on works in progress, and such submissions do not constitute publication.
All rights remain the sole property of the author. Any use or reproduction of stories or critiques associated with stories is prohibited without the express permission of the author.
Critiques become the property of the author insofar as they pertain to the original work, and using critiques you've given that disclose any element or part of an original work by another member is also prohibited without the author's permission.
It is important to recognize that ideas, titles, names, and phrases cannot be copyrighted, and you have no protections or guarantees that an idea for a story you propose will not be used by another. Critique Circle recommends you only post original, developed content if you're worried about someone using an idea you've come up with.