Pangaea666: Given how often this happens and that they're down for days on end every time, they really ought to think about changing host -- unless it's a problem on their own end of some type. Hosting is pretty darn cheap these days, and sites generally don't go down -- ever.
Maybe they are hosting it themselves, with not good enough equipment / security?
It's already noted that it had been a hard drive failure and the site is being restored, but a bit here about domain vs web hosting: they are separate entities, although many web hosts will offer to register your domain for you (often a bad idea, as it makes things more inflexible if you want to move to another hosting provider, and in many cases it results in the domain technically being property of the host rather than you), and most will maintain the DNS records for you regardless of who your domain is registered through (this is generally a good idea as it means your host names will be aligned properly with the way things are set up on the host).
In addition, regardless of how well both your website and DNS are maintained, it actually only takes fairly simple (though unlikely) failures to result in large swathes of users being unable to access your site - as most user-end PCs don't actually consult the "authoritative" DNS entries you/your host maintain directly but instead access them through a DNS server provided by their ISP or by some other party like Google or OpenDNS. These servers, once they've looked up the information once from the authoritative server, hold it in cache memory for a length of time called TTL - so if incorrect data is read or if changes are made to it, many people won't be able to access an affected site until the TTL runs out (causing the end user-accessed DNS server to once again look things up at authority). This is uncommon for established sites (usually resulting when a host moves sites to different physical servers during maintenance, thus changing the IP address of the sites), though on the other hand many people who've just set up a website run into this problem (often when a site is freshly opened, much of the Internet has to wait for one more TTL cycle to run out).
