Adding more detail to What Dave just said, there is a "distributed database" on the Internet which maps from host/domain names (e.g. whatsbestoforum.com) and the actual numeric address of the server (IP address). This translation is mandatory as the computer protocols to communicate relies on having the IP address.
Originally a single service provided all of this who is now called Network Solutions Inc. They were the only registry for new domain names. Once you registered with them, then a set of servers around the world would "cache" the same data so that when you wanted to talk to another computer, you wouldn't have to go to NSI's servers. Today, your ISP provides such a cache as do other third-parties.
When you register a new domain name, it takes a few hours sometimes for the name and address pair to propagate across the Internet. And when you lose it, it also takes a bit of time for it to disappear. This may be the reason why some of us could see Audiogone but others could not.
Companies registering your domain name charge a year fee. Smart thing is to set it up for auto-renewal but this doesn't always work. If your credit card company changes your card number as they do every few years or the expiration date changes, then the automatic billing doesn't work. The registrar will send notices but people forget what email address they put in the record and notices are lost too, leading to domains expiring.
BTW, there is strong federal law protection against someone stealing your domain name even if it did expire. All you have to show is that the domain name is a brand under which you have been operating and you can get it back. Indeed, we had to do that for my business. We had a guy to do the registration for us. As has happened here, I went to do something, and that deleted all the domain registry records. Went to fix it, only to realize I had no authorization to do that! I could delete things but not add it back in!!! Suffice it to say, over a weekend, we lost everything: the domain name, email, everything. I went back to the guy and asked him what is up, and to get control back and he refused! Had to get my attorney involved and $1,000 later, he relented when he realized he didn't have a case.
So be very careful when you get domain names registered. Make absolutely sure you own the domain even if you change ISPs. Some will hold it hostage forcing you to use them forever.
