A "crash" doesn't do that. Someone had to change the DNS entry. DNS (domain name service) is what is used to convert domain names (such as democraticunderground.com) into their actual internet IP addresses, which is a 32 bit number (four octets binary 00000000 through 11111111 which is decimal 0-255 with each separated by periods), for example 2.3.4.5.
The address 1.1.1.1 which technically valid doesn't go anywhere. The link in the OP says that the name used to resolve to 208.42.168.197. This server is up (try it yourself at
http://208.42.168.197). You'll get a directory listing of / (the root directory) containing svnindex.css and svnindex.xsl. There is no actual content meaning someone removed it. It also reports that the server is Apache 2.2.8 (the de-facto open-source webbrowser) running on Ubunutu (a popular linux distribution) with PHP 5.2 (a programming language commonly used for dynamic web content), Ruby (another programming language) and SSL (the secure socket layer) plugins enabled. The interesting thing is that if you select to use a secure connection for the server (
https://208.42.168.197) and accept the security certificate (most web browsers will say there is a problem with the certificate because you requested
https://208.42.168.197 and the certificate is for
https://www.colemanforsenate.com) the page will load, albeit slowly (this is due to parts of the page such as images being located at
https://www.colemanforsenate.com, which doesn't resolve to the "real" IP address and the web browser trying to download each and having them timeout).
No, this wasn't a website "crash". It was taken down on purpose (and rather sloppily).