I had a friend that sold crap jewellery in a street market. He had a big tray full of crap with a sign on it - everything $1. He used to mix the things he wanted to sell in amongst the crap. People used to hunt round and buy them even if they were on his stall somewhere else for 75c, he also used to sell some of the crap now and again. This is the concept I was working on.
Register crap is negative and people won't look, dump implies that they could find something if they are smarter than the guy dumping.
On a technical note. I wanted to sell the name and not the developed domain, so namedump is better. Of course you can include the domain with the name if there is one.