Maybe the YC company only charges advertisers for each impression -- or maybe for each click-thru. If an advertiser's goods are "down-modded into oblivion", th

Maybe the YC company only charges advertisers for each impression -- or maybe for each click-thru. If an advertiser's goods are "down-modded into oblivion", then the advertiser at least didn't have to pay anything. And they can take their ad to, say, AdSense, or some other less exclusive network.