Most people will use the free web space that is provided with their ISP account for their first web site. Often, you end up with a web address, or URL, that looks like one of these examples:
If you plan a web site for a club or business then such addresses will not be acceptable, and even if they are, don't look especially professional and won't create the right image. In these cases you will need to register an appropriate domain name, so your site will have a name taking one of these forms:
Working from the right, these addresses indicate a United Kingdom base. (Registering a ".com" domain indicates that you aspire to become a world-wide company and don't need to be strongly associated to the UK.) "co" indicates a commercial body, "org" indicates a non-profit organisation and "me" is reserved for personal sites. Other possibilities include "ltd", but there are strict rules requiring the use of your exact company name for these domains, and even "net" which is intended only for businesses offering internet services to their clients, rather than those who offer on-line purchase of their goods.
The "cheapest" form of registration is with a service that offers "web forwarding" only. A visitor will enter the URL in the registered address in the browser address bar but, by the time the page opens, all trace of that URL has gone and you see the actual hosting location displayed, usually the hosting company's domain followed by all manner of slashes, tildes and other long winded stuff that makes the site appear less than fully professional.
Next up is "Forwarding, with Masking", sometimes known as "Gripping". This keeps the domain showing in the browser address bar regardless of the page on the site currently being viewed. This is achieved by the hosting service using frames. From the perspective of the site's creator frames are irrelevant, so the fact that KompoZer doesn't support them is irrelevant. As with forwarding alone, search engines will show the true location of the page, and so it can confuse potential visitors if they are planned to visit your site, but can't recognise it from the URL given.
Finally, and most expensive, is what I know as "Cloaking", where the folder on the hosting server is made invisible to the site visitor and is replaced by the registered domain name. With this, the browser address bar accurately reflects the location, within the folder structure of the site, the file currently being displayed. Search engine listings show the same address for the page as the the browser address bar shows. Site owners can direct people to a specific page, rather than just point them at the home page and tell them to follow the links to the desired page.
Not all registration companies use the three terms Forwarding, Masking and Cloaking in the way that I do here, so you have to be careful about the service that you are buying when registering a domain. Which service you choose will depend on which of the features are important to you, and the depth of your pocket!