There are many different types of domain name. By far the most popular (and hence "valuable" if you are considering registering domain names as an investment) is a domain name ending in .com. These dot-com domain names are used by the vast majority of large companies, who have been spending hundreds of millions of dollars on branding the "dot-com" top domain in the minds of web users worldwide. In fact, .com names are so widespread that many people don't know other domain extensions exist! .com domains can be freely bought or sold by anyone.

.com domains should be considered the equivalent of prime real-estate on the Web. Most companies will place a premium on owning a .com name over any other domain extension.

Two other international top domains, .net and .org, are becoming increasingly popular. .net is officially reserved for network associations such as ISPs, but in practice anyone can register a .net name. .org is supposed to be for non-profit organizations, but again this rule is not enforced and anyone can buy .org names. You should think of .net and .org names as distant cousins to the almighty .com, less desirable certainly but not unbearably so. Anyone can register .net and .org domain names.

Most countries now have their own top domains, such as .uk for the UK or .fr for France. The rules for buying domain names under each country top domain vary from country to country; always check before you buy!

Some countries have essentially sold their cyber-rights to enterprising entrepreneurs. For instance, anyone can pick up a .to domain name (Tonga) or a .cc domain name (Cocos (Keeling) Islands) and most people are not even aware that these were intended to be country-level top domains in the first place!

Some companies are selling sub-domains of memorable domain names. For instance, you can buy a sub-domain of .uk.com if you could not get the .uk domain name you wanted. These are NOT official, internationally sanctioned top domains, just companies essentially chopping up their own domain names into smaller pieces.

	You may have read about plans for several new top domains. 7 new top domains have been approved, but there are still a large number of disputes to resolve, and steps that have to be taken, before these new domains become available to register. The earliest these domain names could be introduced is mid- to late-2001, though the process of introduction is likely to stretch even longer. Therefore, don't be fooled by companies claiming to be able to sell you domains under these new top domains (.biz, .info, etc.) already... they are selling you the POTENTIAL that maybe you'll be able to reserve the name one day, IF the company manages to become an accredited registrar AND IF they beat all the other new registrars and manage to register your pre-reserved name first. Far too many IFs for my liking; better to save your money and wait until the new top domains are official!

The choice of which top domain to register your domain name under depends on availability, on the impression you want to give, and on the reason why you are registering a domain name. Country-level top domains are often firmly associated with that particular country, so if you are working in an international company or organization, you're better off buying a .com name. However, over 9,000,000 .com names have already been registered, so supply is very tight and you may have to compromise with a .net name. If you do business in one country but you also want to appear as international as possible, reserve both the .com and country-level top domain versions of your new domain name.

	If you are buying domain names as an investment and you are VERY confident that the name you have chosen is valuable, it can be worthwhile securing the .com, .net and .org forms of the domain name. That way, nobody can "undercut" you when you come to sell the name by offering a different extension cheaper. The downside, of course, is that you'll be paying 3x the registration fee! With prices dropping all the time, this is no longer the expensive proposition it was only 18 months ago. You can follow the same approach to secure your company or brand name against people trying to cash in on its popularity.