I have this book on my TBR list, and was wondering whether it would be ok to post it or not when I'm done reading it.

The book is this:

http://www.paperbackswap.com/book/details/9780843955439-The+Girl+Next+Door

(paperback copy of The Girl Next Door)

I have reviewed the PBS posting guidelines, and I'm not sure where my book falls, you see, it has a partial thickness tear on the back cover, about 1 inch high by 2 inches long.  It is not completely severed from the book, nor actually torn in pieces, but instead looks like someone tried to peel a sticker off of the back and failed, tearing the glossy part off of the cover, but not tearing it through and through.  I hope that makes sense.  What should I do? Post it? Or not? Many thanks!

I think any tear over 1 inch makes it unpostable, even though it's a partial tear.

It sounds like the cover is peeling?  I'm not sure if that technically qualifies as a "tear" but I would err on the side of caution and offer the book as a freebie in the bazaar.  (Or, what I frequently do with grey area books, swap it for something postable at the UBS.)