What is Online?

The term online refers to a device or service that is available for immediate use. Typically the word is used in reference to the Internet, with online services being any service that is accessible via the World Wide Web or other Internet interface. People can also said to be online, usually in the sense that they either are currently logged into an instant messaging or chat service, or in the more general sense that they access the Internet frequently. Most major government agencies, banks, and universities are online today providing information, services, and even degrees over the Internet. Online dating websites have surpassed their traditional offline counterparts in terms of membership and revenue. Online casinos provide legal betting and gambling services throughout the world, and are especially popular in areas where traditional brick-and-mortar casinos are illegal. Online shopping and auctions have brought new products to every corner of the globe, including places where Internet access is extremely limited or expensive. Additionally, online shopping has broadened markets such that products with limited appeal or demand are now feasible to produce and distribute.

Online is a portmanteau of "on the line," a reference to the physical connection's cable or line. The designation of online was originally reserved for computers that were connected to a network and were running services that answered on that network, such as online printing. While some computers in the late 1960's were capable of sending messages and accessing other machine's resources, these machines were not termed 'online' as they did not answer on the network. With the development of email systems that routed mail for other machines, the computer that only handled outbound connections became a rarity. As the routing of email was often specified manually by the sender at the time, all the computers of the network became vital components of the network. More reliable hardware components allowed computers to be powered on almost continuously, and their immediate availability was not only demanded, it was often expected. Thus, computers were deemed to be either 'online' or 'offline' (batch) machines.

A less common use of the term online today refers to peripheral devices connected to a computer. Printers, scanners, and other external peripherals are said to be online when they are physically connected to the computer and configured to exchange data with the computer. Although still connected to the computer, a peripheral is termed offline when it is either powered down or not configured to send/ receive data to/ from the computer. Internal peripherals such as hard disks, sound and network cards, memory, and floppy disk drives are said to be online when they are mounted and functioning. Unmounted hard disks, inaccessible memory, and disabled network cards are said to be offline.