You can't tell which ads will get clicks. It seems that ebay does not bring in much. However, if you pick them carefully (Amazon and ebay), and not just to use the capsule, chances are better that you might get a click and maybe a purchase. Make sure the ad is strongly related to your hub and is something that will interest the reader. Is it something that the reader is likely to use based on the information you provide? Is it an obscure item that he won't find in a store? Even though the earnings are relatively low, you never know when you might get a hit. Soon as I said I was going to stop using ebay, I got a couple hit in one week. Only pennies but they do add up.