They don’t care. In fact, in most cases, the spammer is not the merchant. What usually happens is that someone (third party) is paid some small amount – maybe 10 cents per website to post crap like that. They work from home for an hour or two each dat and make a couple of dollars. Not a great salary, but for someone in India or Thailand or Philippines, it’s income. The merchant contracts for, say, 1000 posting per week anywhere on the internet. The merchant pays $50.00 . SOme percentage of these will turn into sales, which makes it worthwhile. So the spammer himself is just a piecework drone, and has no stake on whether the item sells or not.