If you mean will having ebay ads on your hub cause you to get a "penalty" in the search results, the answer is no. If you're wondering if people are going to click on the ebay results instead of the google adsense ads on your hub...well, nobody knows. Different traffic sources behave in different ways. Some people who click on ebay ads would never click on Adsense ads anyway, so there would be no loss. It's more likely that some of the people who would have clicked on adsense will instead click on ebay ads and thus your revenue will be split. This can be good or it could be bad.