The Domain Name is most important part of the URL. If you do not understand URL, this earlier article here: http://topp.home.mchsi.com/filenotfound.pdf includes my attempt to explain it. Simply put, the URL is the name of a file on a computer on the Internet that a user is trying to have their computer contact. Of course, all locations on the internet are really known among computers by their IP address, you know, like 216.239.37.99. But, words, like "google.com" are so much easier for humans to remember. And they both have the same result.

The Domain name is the first part of that URL, and anyone can have one. Having a domain name does not give you anything except a reservation on the name (meaning no one else can use it). It is not necessarily connected to the Internet until you activate it, and tell it what to refer to. For us folks with failing memories, it is important to reduce the number of things we have to keep track of. I already have to remember my own name (Mick Topping), so wouldn't it be nice to be able to tell people that my email can be sent to mick@topping.com? Well, topping.com was already taken, but I found a pretty close substitute. Domain names can be up to 67 characters in length, including the ".com", ".org" or ".us" etc. which means you have 63-64 characters that you can specify on your own. (I like the patriotic aspect of the ".us" domains and these names are on sale at godaddy this month). Letters a-z and numbers 0-9 plus the dash character are all ok, but your name should not start or end with a dash, and should be all lower case. My experience has been that domain names can be typed in either upper case or lower case with no difference, but no guarantees. (By the way, some references say that names containing the "7 forbidden words" from network TV are not registerable.)

I am not an expert on the registration process. I used http://buydomains.com/ as my first registrar, because when I started 5 years ago, they were pretty cheap, and also I like the extra services that they throw in, like domain and e-mail forwarding. I recently registered another organization's domain name there, so I am still happy with them, but transferred my personal domains to http://godaddy.com because of a slightly better price, and a better email service. Since I have not used others, I will focus on these companies as examples.

If you go to the buydomains or godaddy web page, you get a search window (several actually, but you probably don't want one of the "premium" names.) Anyway, figure what name you would like, and see if it is already taken. Now if your name is Jim Smith, you are going to have to be imaginative. Like you may have to use a name like jimzmith.com or jimsmith-son-of-bob.com. If you have a fairly rare name, but it is already taken with the .com suffix, don't forget to check ".net", and ".us". So, just add to your cart, (anywhere from $5 to $15 per year) and give them a credit card number (never give a credit card number on the Internet unless the receiving page is an HTTPS not just HTTP-and make sure the little pad-lock is closed in the lower-right corner of IE). Shazam, you are the owner of a domain name. Be advised though, you do not have anything but a name at this point--no webpage space, no email service, it doesn't do anything...

If you want it to really do something, you must first have an email service and web-space, then you have to go to the buydomains or godaddy setup page and either set up the IP address to which the name should be assigned, or configure domain name and email forwarding. The IP address is mostly for the big outfits who have a real connection to the internet, not us small fry who are working through an ISP. For us, you are essentially telling your domain registrar to assign your domain name to their own server, and then to forward mail and webpage queries to another name.

For example, if you type in mtopping.us in the address bar of IE, it sends a request to the godaddy forwarding server, which forwards it to my real webpage. For email you can have any email that is sent to (e.g.) jim@smith.com forwarded to your real email, jimsmith497@huge-isp.com ... This also gives you an email cut-out, so you can, just by juggling your settings at buydomains or godaddy, change your email address, and leave some of that spam in the dust (of course, you leave your friends also...)

As I mentioned, I am no expert, I can only testify what has worked for me. So take the above with large dose of skepticism… Do a little research on your own…

You can become the world's foremost authority by reading up on this stuff at:
http://www.internic.net -- they are the charter authority for domain naming rules.
http://www.0dns.org/ -- good reading about this whole issue, even some free registrars.
http://dmoz.org/Computers/Internet/Domain_Names/Resources/ -- a source of sources.
http://registrar.godaddy.com/default.asp?isc=good1001g - my favorite registrar as-of today.