It's the rating id of a post ratings rating (like = 1, etc.)
Probably not something most people will need but I found on my forum that the highly 'emotional' posts with large numbers of friendly ratings dominated the interesting/funny posts, so I've got the friendly rating blacklisted
Ahh I see, its part of the Post Ratings addon, no wonder I was confused.
A post ID blacklist would be cool. There's quite a few announcements from admins on my Best Post's lists that don't really need to be there.
Thanks again for this addon, my members have been asking for it since I moved from vb + vbseo.