Well I'm not getting rich by being an eBay affiliate, but I am making a few dollars here and there.
I own a large website for Golden Retriever owners. I know there is a percentage of them who will buy just about anything with a Golden Retriever on it. On my sidebar I use ShoeMoneyAds to display a vertical banner with the next 3 ending auctions. The photo of the item captures their attention. I believe there is also a cookie so if they click through once and return to eBay within a certain time period, I'm credited for that sale or bid too.
If you have a site that is very focused you could do well with eBay. Treat it as another stream of passive income. I'm planning on doing a massive overhaul of my site's design so I can work in the eBay ads better for more clicks.