Note that there's another equally-simple explanation that fits all the facts gwern posits here:<p>1. The MtG app was hosted on a subdomain (CNAME record, no A record) that sometimes had an accompanying apex-record lead-gen website to "sell" it, but usually didn't. (When you're an engineer making a webapp, writing the lead-gen copy is usually the last thing on your mind.)<p>2. The app subdomain served a robots.txt that prevented the Internet Archive from indexing it--as is usual practice with app subdomains.<p>3. McCaleb doesn't generally want to talk about how his site used to host an MtG exchange, because that'd make people less willing to take BitCoin seriously. He doesn't <i>deny</i> it, though, nor use the misapprehension as a source of humor in interviews. He just clams up.<p>I'm not saying gwern is wrong, but he hasn't inviolably proven his hypothesis yet, either. I look forward to a comment from McCaleb, if there ever is one. (My own hypothesis would support McCaleb never responding to gwern's query.)