A third level can be defined to identify a particular host server at the Internet address. In our example, "www" is the name of the server that handles Internet requests. (A second server might be called "www2".) A third level of domain name is not required. For example, the fully-qualified domain name could have been "aalphanet.com" and the server assumed.

Subdomain levels can be used. For example, you could have "www.nyyankees.aalphanet.com". Together, "www.aalphanet.com" constitutes a fully-qualified domain name.

Second-level domain names must be unique on the Internet and registered with one of the ICANN-accredited registrars for the COM, NET, and ORG top-level domains. Where appropriate, a top-level domain name can be geographic. (Currently, most non-U.S. domain names use a top-level domain name based on the country the server is in.) To register a U. S. geographic domain name or a domain name under a country code, see an appropriate registrar.

On the Web, the domain name is that part of the Uniform Resource Locator(URL) that tells a domain name server using the domain name system (DNS) whether and where to forward a request for a Web page. The domain name is mapped to an IP address (which represents a physical point on the Internet).

More than one domain name can be mapped to the same Internet address. This allows multiple individuals, businesses, and organizations to have separate Internet identities while sharing the same Internet server.

To see the IP address for a domain name, (ping).

It may be worth noting that the domain name system contains an even higher level of domain than the top-level domain. The highest level is the root domain, which would be represented by a single dot (just as in many hierarchical file systems, a root directory is represented by a "/" ) if it were ever used. If the dot for the root domain were shown in the URL, it would be to the right of the top-level domain name. However, the dot is assumed to be there, but never shown.

Selecting The Best Domain Name

If being found in the major search engines (Google, Yahoo, etc.) is important to you, I highly recommend you register a name that contains your major keywords instead of your company name. 

Think about it.  The average surfer searches by subject, not by proper name.  So why it may seem cool to have a name like TimothysToolTyme.com, you'll want to choose a name that includes keywords that your target audience would likely use when they search.

Sure, you can still list your company name on your web pages, but I believe it's more important to make sure the domain name includes your important "search friendly" keywords if you want to receive traffic from all over.

Of course, you can still list your company name on the web site some place, but your domain name will include all the important keywords you'll want to be found with.

Now, as always, there are exceptions...

If you are just creating a website for a local business, getting traffic from all over the web may not be as important to you.  This is because your customers will be local and you may want to grow your brand name in a specific area.

If this is the case, it may make more sense to register your company name and create brand awareness locally instead of trying to capitalize on search engine presence.

For example, let's say you have a company called J.W. Reed & Co and you help people get rid of debt, but you're based in Kansas and can only cater to residents in this area. 

Since you are only servicing local clients, you may not care if someone in California can find your site in Google since they are not likely to become one of your customers. 

In this case, it's not as important to register a name filled with "search optimized" keywords.  You may decide to just reserve the company name, JWReedAndCo.com.

NOTE:  Keep in mind that the domain name is not the only factor weighed by search engines when deciding your rank. 

The content on your web pages and your site's popularity (inbound links from other sites) is very important too. However, it certainly doesn't hurt to make sure your name is optimized for maximum results.

Here are some more tips on choosing the best domain name:

1) Don't register domain names that are too long and have too many syllables if you can help it.  Yes, you can register names up to 63 characters long, but that doesn't mean you have to use all 63 characters.

You want your name to be easy to remember. Not everyone will bookmark your page initially so try to think of something that can be easily remembered -- although I realize this may be tricky since a lot of names are taken these days.

2) Use hyphens if your name is more than 3 words long (unless your name includes 3 short words).  A name like carbuying.com doesn't really need a hyphen because it's readable the way it is.  

However a name like used-car-buying-scams.com looks better than usedcarbuyingscams.com since there are so many words in the name.

3) Protect your name by registering multiple extensions (.net, .org, etc.)  This deters people from copying your name. For example, if you own garden-tips-for-us.com you can also register garden-tips-for-us.net and any other extension that's available.

You don't have to build a site on all the domains, but you can reserve the others to keep people (copycats) from registering them.