You may hear this term when you move your Web site from one server to another. Put simply, it's the transmission of signals from one place to another. On the Net, it works like this: When you move your Web site from one IP address to another (by changing the server it is hosted on), the DNS must point to the new address. Once you make the request (with your ISP or with InterNIC) to have the DNS point to the new location, it may take 48 to 96 hours (or even up to 5 days) for all of the networks to process the change. This is because the Internet exists on many different networks. You could see your site listed under its new IP address using PacBell phone lines, for example, but a friend trying to look at it from another location using NYNEX phone lines, for example may not see the new address until the propagation takes full effect.