Introduced as early as 1983 (yes, the Internet is that old ;-) DNS provides several key functions:

• A "phone book" for Internet addresses. Each domain name maps to a single numeric Internet address
• "ZIP code" for e-mail delivery. The part of your e-mail address that is behind the "@" sign is the so-called MX-Record; it maps to another domain name or numeric Internet address pointing to the destination e-mail server
• The basis for "virtual hosts". Without DNS there would be no Web hosting business as we know it. By letting multiple domain names point to the same numeric address and thus, the same server, multiple Web sites can be served from the same host

Each domain name (e.g. "bmweb.com") is made up of multiple parts that are concatenated by dots ("."). Originally, only English-language characters were allowed (so called "ASCII" characters). Since a few years now, the standard was extended in order to allow also for other character sets - mainly for supporting Chinese domain names.

Domain names are "resolved" by domain name servers from right to left. The right-most part is called the "top-level domain". Each domain name consists of two or more parts. Each domain server is responsible for one part; finally, the left-most part resolves directly to an IP address.

Everyone can host their own domain servers in order to sub-divide his or her domain into so-called "sub-domains". If you only need to do the final mapping you can typically use a hosted domain server (typically hosted by your Web site hosting provider); this is called "domain hosting". Only the top-level domain servers are run by special organizations and have well-known IP addresses in order that their domains cannot easily be "hijacked", i.e., taken over by a hacker.

Originally, there were only a few top-level domain names (.com, .org, .net, .gov) with each having a very specific meaning and purpose. As more and more servers were deployed on the Net, these top-level domains were extended by their newer counterparts such as .name and .info. It still makes sense to choose a top-level domain that "fits" to what kind of information or service you want to provide:

• .com denotes a commercial business site
• .org refers to non-profit initiatives and organizations; often also used for open source projects
• .net was originally meant for networks and Internet providers
• .gov is used by the US government
• .name was intended mainly for private Web sites
• .info is for any kind of information, but is also commonly used were .com was already taken

In addition, there is also a top-level domain for each country based on a 2-character code for this country (for instance, .de for Germany, .ch for Switzerland, .uk for the United Kingdom and .at for Austria). Choosing such a top-level domain makes a lot of sense if your initiative, service or business is tied to a specific country or region.

There is a lot more to domain names, but this post is already too long. So let's close it by mentioning that you need to register a domain before you can use it (for instance, I have registered and, therefore, own the domains blackmagicweb.com and task1.info). And if there is not a very-well known trademark that conflicts with a given domain name, everyone can register any domain. In other words, domain names are assigned on a "first come, first served" principle.

So, if you want a specific domain and it is not yet taken, I suggest you go get it now... ;-)