As far as I can tell, the domain name itself expired yesterday, and the registrar eNom has helpfully decided to cease providing correct DNS information with immediate effect: their service at name-services.com is now returning the IP 8.5.1.36 for btct.co queries instead of the IP 141.101.113.21.

I am not recommending the following, because many people will rightfully expect a signed, sealed, and gold plated confirmation from Ethan before trusting any information about iP addresses, but if you were to place the original IP address in a hosts file, and clear your DNS cache, you would then find that the site is still very much alive and kicking. I have just done this myself and could see the last trade shown on the front page was only 49 seconds ago, so either people with cached DNS information are still able to get there, or the problem was resolved while I was typing.

The registration itself should have a grace period, and abruptly ceasing DNS services for the domain does not, in my view, speak very well at all for eNom.