Those are just "machine names" (if I'm not mistaken) assigned to IP numbers/machines. For example... my ISP assigns me a new "machine name" every time I dial up to the internet, and the format they've chosen is ppp1234.myisp.com (the number changes each time I dial-up). Other ISPs may choose not to assign machine names, in which case I'd get a different IP number every time I dialed up...
Each of those cryptic names should correlate to a specific IP number, just like a specific domain name (ie- foo.bar.mysite.com) would correlate to the site's IP address (ie- 0.12.34.56)
mivox's "machine names" are more properly called domain names. The numeric versions are called IP (Internet Protocol) addresses. Domain names are a more human readable form of an IP and, as mivox indicated, they both point to the same site.
Each computer connected to the Internet has a unique IP address. Dialup users typically get an IP assigned each time they connect, called a dynamic IP. ALL of the information packets scrambling around between computers on the web use IP addresses to get from computer to computer.
Domain Name Servers do the conversion between domain names and IPs. IPs are usually translated into domain names to make it easier on human users, after a packet or series of packets reaches it's destination.
A request from your browser for www.yahoo.com initiates a DNS lookup. The IP for yahoo is returned to your browser from your assigned DNS server. Your browser then sends a series of packets requesting info to the yahoo IP. Yahoo responds to your IP...
A good overview of how it all fits together is here [xoc.net].
Somehow, I'd gotten the impression that "domain name" referred to the name assigned to a website, and "machine name" referred to the name assigned to a surfer's or network's internet access machine, even though they were functionally the same thing... Dunno where that came from. :)