No big loss. It was horrible. We tried it a few times. Millions of impressions, but very few clicks. I think we would have just as many clicks if the ad was invisible. I've seen some people say things like 75 clicks in 10 million impressions when they ran it. That's an incredibly low click through rate.
The bad part to all of this is that they'll probably replace it with ads they sell themselves and they wont be as friendly towards linking to eBay items like they do now.