Doug,
You seem to be asking why do some banner ad holders contribute by posting and others do not? I have no answer for that one, but I am thankful that they support us by buying an ad which helps keep GDC, including the ability to upload picture, free.
Same applies to Premium Members. Do they have to post in order to sell? Absolutely not ! Look at Bob Grant - Bygone Relics - who rarely contributes but continues to give GDC members first shot at a fantastic variety of "vet p/u" artifacts. Good for him.
Dave
