Concept Feedback.com is a free community where designers and developers can exchange feedback on design projects. Registered users have the ability to post marketing concepts for free. Concepts may include, but are not limited to, websites, logos, newsletters, landing pages, advertisements and videos.

Reviewers can offer constructive feedback on each concept using a proprietary feedback tool. Feedback is automatically collected and archived for the user to help improve the final concept and get better results. In addition to a distinctive professional network, registered users have the capability to post concepts privately, for secure review by clients, co-workers, and friends.

http://www.conceptfeedback.com