Two things that a lot of internet novices get confused are domains and web sites. Often they ask questions referring to one when what they actually mean is the other. Hopefully the following explanation will assist web novices to understand what the difference between these two are and be able to ask less confusing questions.
To make it easier to understand I am going to describe something you are probably a lot more familiar with that also has two different things that have a similar relationship. These two things are your house (or apartment) and your address. Both can be considered to be "where you live".
If you own the house that you live in then you are in the position to be able to make changes to that house. These changes can be simple maintenance such as vacuuming the carpets or painting the walls or extensive renovations such as adding a new room.
Even when you own the house, making changes to your address is a lot more difficult. To be able to do that you would need to jack up the whole house and put it on the back of a truck. The truck would then take the house to the new address where it would be lifted off the truck and placed onto its new foundations. Occassionally someone does relocate a house like this but it certainly isn't something that many people consider. Normally people change their address by moving into a different house tat is already at the new address.
So let's look at how this relates to domains and web sites. A web site is like a house. Removing broken external links is like vacuuming the carpet and making mchanges to your page template is like repainting. Adding new web pages to a web site is far easier than adding a new room to your house.
The domain is the address of the web site in the same way that your address tells people where to find your house. To be able to change your domain means moving your entire site. First you need to purchase the new domain, next you copy everything from your old domain to your computer (placing the house on the back of the truck), and from there upload the site to the new domain. Moving your web site from one domain to another is certainly easier than moving your house from one address to another but still involves a lot of moving things about.
So making changes to your web site is relatively easy (and will become easier as you become more familiar with the tools you have available). Making changes to your domain are much more difficult because it involves moving your whole site.
When you change address you most likely made arrangements with the post office to forward your mail for a short period so that it doesn't get lost. Similarly when you change domain you will often want to arrange for the old domain to redifect to the new one for a period of time so that your visitors can still find your web site.
This article written by Stephen Chapman, Felgall Pty Ltd.