A device on the Internet needs its own address to receive data, just like a home or business needs a street address to receive physical mail. This address is its IP (Internet Protocol) address. When you connect to a web site or other server online, you usually reveal your own IP address. This doesn't necessarily reveal either your identity (it's hard to map an IP address to a real address or a particular computer). An IP address can give away some information about you, however, such as your rough location or the name of your Internet Service Provider. Services like Tor let you hide your IP address, which helps give you anonymity online.