I often have to explain to clients why, when they first get a domain name and website, it takes up to 48 hours for someone to be able to see their website. This can happen if they switch web servers, as well. The key to understanding this is understanding a little bit of how domain names work.

Keep in mind, this explanation will be just a bit simplified, to make it easier to understand. I don't like filling my explanations to clients with technical jargon, so I'm going to attempt to avoid that here.

The first thing to understand is this. Web hosting (or web space) is completely different from your domain name. Where your website's files actually sit has nothing to do with what your site is called. In fact, you can even purchase your domain name from one company and your web hosting from another. Many people do.

So how, when someone goes to your web address, does it know where your web hosting is? Each web host actually has a numerical address. Let's say your web site is at www.yourcompany.com, and your actual web hosting address is 216.60.153.87. How does my computer know that by typing in www.yourcompany.com, it should actually go to 216.60.153.87?

It doesn't. Instead, it asks my Internet service provider (Cox, AOL, SBC, etc.). Each Internet service provider has all that information stored. So my computer sends my ISP the web address, www.yourcompany.com, and my ISP actually looks that up at 216.60.153.87.

Hopefully that clears up a little bit the association between the domain name (www.yourcompany.com) and what is referred to as the IP address (or name server) of your web host (216.60.153.87). Now, let's move on to why it takes up to 48 hours to update those records.

Let's say you buy a new domain name through Go Daddy. For every domain name someone buys through them, Go Daddy has their domain name and actual numerical address stored. That's thousands of domain names. But when you buy a new domain from them, at the beginning, they're the only ones who have that information. They then have to get that information out to the rest of the Internet.

So how does that happen? Let's use an analogy. How that spreads is similar to how the flu spreads. If you were spreading the flu on purpose, that is. Let's say you had the flu, and wanted to spread it to as many people as possible, but could only infect one person at a time. The key, then, would be getting those people to then also infect others.

That's how the spread of your domain name works. Go Daddy (or whoever), regularly contacts other computers out on the Internet and passes on this information. Then those computers do the same. However, one computer might send out this information every hour, another every six hours, another every fifteen minutes. The schedule of each computer is not the same.

So 48 hours is the maximum amount of time, the experts agree, that it will take the information about your domain name to spread to all those computers (called domain name servers, or name servers for short). The technical term for this, if you're interested in knowing, is propagation. 48 hours is the maximum amount of time it takes your domain record to propagate to all the domain name servers on the Internet.

As complicated as this sounds, I've actually simplified it quite a bit. But the essential concept is there.