Pretty much exactly what it sounds like it is. This is the place to discuss and assist in the community development of F18, post Alpha.

WARNING: Any pre-release versions, Beta included, are for experienced testers only. Back up all existing data and read all threads in the version Development Forum before attempting an install. Errors can and will likely occur which may include data destruction or inability to boot other partitions on any and possibly all attached hard drives.

While FedoraProject needs and appreciates testers, you must remember to report issues directly to Bugzilla, after checking for pre-existing bugs.