No. It's actually not hard. It was for an art reseller in Greenwich, CT, they held an art auction that was simultaneously online and in-the-flesh. I had account registrations, search (with image results), anonymous bidding, outbid notifications (via email), winning-bid notifications. I implemented the whole "what's the highest bid you would accept" functionality (also not hard). I did not write the frontend (a friend did that) and I didn't handle payments nor shipping (winners were expected to go to the physical store). Hence "ALMOST" all of eBay's functionality. :P

Either that, or I'm just a really good programmer under pressure (I pulled an all-nighter for that one), which I would not disagree with, I've basically been coding since I was 12 in 1984, so I would HOPE that I'm somewhat of a force to be reckoned with at this point. ;)