cut the corner off of the book??  I have been seeing this on a lot of book lately and was just wondering

it is another type of remainder mark

I've seen second hand stores that do that to mark books that they've sold and won't take back on trade.

wouldn't be such a big deal but, I've been seeing like almost have the front cut off with that corner, as far as PBS this makes them unpostable and these have been some WL books.  Didn't want to take the risk of buying them and then not finding a home for them since these were books I'd already read.

ok thanks I see it alot and couldn't figure out why it was being done

Books can be missing up to about 1 square inch of cover and it is still postable.

So, your books with the corner cut off are OK to post.

I think the rules specifically mention this exact case as postable, in fact.

Yup, Sara's right, this case is mentioned specifically in the Help Center:

Cover not torn or chewed/gnawed

• some used book stores cut out a small part of the cover; if the amount missing is less than 1 square inch, this is OKAY