I dont really look at it as wasting time. I for one monitor my site all the time and I cant help but see the ads that are displayed. I personally have a very low CTR, and that is what I am trying to address. Like right now "Discount fantasy football draft, check out the deals now" nobody coming to my site is going to be interested by that. I would rather have an ad that pays a penny lower and gets clicked than this nonsense ebay trash that is smothering my site. For me, it is now a point of filtering (which I just started) Next step is complete removal of adsense as it is not much of a money maker for me lately.
You might want to consider that those ads keep showing up because people keep clicking on them, which means they are converting. G's ad ranking system takes into consideration the percentage of a particular ad being clicked on, and if it's high, it gets moved up to the front to encourage more clicking.
That may be the case, but I dont think so. two of these ads will take up an entire leaderboard and they seem to stay stagnant on there. My problem is since these ads began showing up my CTR has severly dropped.
have you heard about Smart Pricing on Google? They give lower bid on site having low CTR. So if you have plenty sites, just choose sites with CTR higher than 15%. This way you'll get better ad bid.