I think most people don't really care about 
signing up for another service...so I have had 
plenty of people bid on cels even when I don't 
take paypal.  I think the only thing paypal is 
good for is for international orders...since 
international mail takes longer...and yahoo 
paydirect doesn't take international sign ups 
(at least, I don't think so).

I've had several people sign up for yahoo 
paydirect after they asked me what it is.  The 
only thing is the first time you sign up for it..you 
have to verify address...which is a hassle for 
only the first time.  After that, everything is fine.