Flip is a great tool for peer-to-peer feedback OR for instructor-to-student feedback.
Flip Videos
Students can reply/comment on each other’s videos via text, audio, and/or video. Because it’s asynchronous, students have time to review the content and plan their response.
Written Assignments
Written assignments can be useful in Flip for peer-review.
Although students cannot upload PDFs to a post, they can video themselves discussing another students written assignment.
They can open the PDF on their computer, share their screen, and discuss the paper that way.
Helpful Websites
There are a few articles written about peer-review on the web. Most are directed at K-12, but the same concept easily translates to all levels of education.
https://www.youtube.com/watch?v=EB2CJlfHIow