In computer lingo, IP stands for "Internet Protocol". You'll often see it paired with TCP, "Transmission Control Protocol." Together, TCP/IP allow two different computers to talk back and forth over the internet.
Every computer and server (email servers, IP hosts) has an IP address.The IP address acts like a return postal address stamped on packets of data that your computer sends through the internet.
IP addresses are made of four numbers separated by periods, for example, 126.96.36.199. This stamp on data sent through the net tells receiving computers what country, service provider, host, and computer sent the info.
Some routers and software can make you anonymous over the internet by masking your IP address. In addition, less scrupulous computer masters can take control of a remote computer and thus have that computer's IP (return address) stamped on their evildoings.
~ Chris (worldstart.com)