I got a pretty angry response from a member, and I would like to block them in the future.  I was wondering how to do that.

You can't.  If you are wanting to block someone from requesting a book from you because of a past trade, with FIFO, the odds of them getting another book from you are slim. 

Patty, if their response was abusive, you should report it to the PBS team using the "Contact Us" link at the bottom of any PBS page. 

Unfortunately no, but the good news...PBS has a large membership, and you are unlikely to run accross this member again.

I think TPTB should provide a function that a member can put someone on a list that they don't want to deal with. This list of course would be private and could only be viewed by the member creating it.

-RD

Thank you everyone for your reply.