If you are looking for an effective tool to help the review of design drafts, providing the ability to add comments, suggestions, to highlight problems or to contribute new ideas, Concept.ly is definitely worth a try.

This new web app allows you to upload just about any type of image file that needs to be showcased, organize it with other related files and to share it with your selected teammates or customers.

Key additional features include:

- Compare multiple designs back to back

- Support for mobile devices

- Link different images and pages easily

- Track progress and statistics

- Full support for Dropbox, GDrive, Box.

P.S.: Free to use for a lifetime if you join the beta program now.

Try it out here: http://concept.ly/

Tour: http://concept.ly/features.html

Great idea for honet feedback.