I've just seen this on Screenplay Productions' website. Looks like it's a new way to have your script evaluated...
"As a novel way of engaging with new and up and coming sitcom writers we've established an interactive submission system whereby registered writers get a chance to learn about, read and evaluate scripts by peer writers. Both writers and readers are anonymous. The prerequisite for getting our Comedy Development Team's undivided attention to your own script(s) you must first deliver to us quality reports on three scripts by other writers, and equally obtain feedback from three other writers in conjunction with a scoring system which will flag up the rough-cut diamonds.
The first 15 writers to sign up will get their first submitted script placed on the anonymous list of available works up for evaluation without having to provide feedback for others first."