I think ebay sells for alot of reasons.   some 
people are not AWARE of cel-sale websites, and 
thus they only see cels for sale on ebay, even if 
you link to your site on your auctions, they may 
or may not see that.
Alot of people I think trust ebay more than they 
do private sellers who ARENT on ebay.  its silly 
really since its the same sellers often... but 
alot of people see ebay adds on tv and radio, 
magazines, and they dont know much about the 
internet, they're just going to this site they 
heard about... and then they go "oh, I can buy 
cels?"

and then you get those same people going "wow, 
that's a cel of Heero from gundam wing! $700 what 
a steal... I bet its super rare" and they buy it.