AFK (Away From Keyboard) gaming is a technique used typically by multiplayer online role-playing gamers, but also can be theoretically used by any other game genre. AFK gamers use software, either in the form of a bot or a game's built-in macro system, to continuously do a repetitive task for them, over and over. It also gives the player a significant competitive edge against other players.
AFK gaming is an oxymoron: it's a way of playing a game without actually playing it. Instead of the player doing the work, his computer does it for him. It is typically frowned upon by the gaming community, but widely used for its many advantages in time]/reward payoff.
Most MMORPG titles are notorious for requiring a player to continuously and repetitively do the same task. Extensive repetitive gaming leads the player to feel "robotic" in that he is constrained to the same repetitive task that requires little or no thought. It is from this type of gameplay that traditional AFK gaming arose.
Farming, the practice of killing massive numbers of easy enemies, is often a goal of these gamers. Since these farming bots run for long periods of time, it allows the player to gain large amounts of experience points or in-game money and items. Even though easy enemies yield low experience points, AFK farming is useful because it allows the player to gain considerable amounts of loot and experience points while he or she is away from the computer (often sleeping, working, or at school).
Games that utilize a crafting system (allowing the player to build an item) can be especially tedious. Crafters often feel as though they are not truly building an item, but simply navigating through various popup windows, clicking the exact same buttons. With a bot, this can be performed quickly and efficiently, greatly increasing the speed at which one can craft items.
Other games, such as Star Wars Galaxies also include social classes, such as musician or entertainer. Because songs and dances are performed almost automatically, there was almost no practical need for the player to be present. Compounded with the loneliness of "ghost towns" inhabited by nothing but AFK gamers, it quickly turned a social gaming experience into the least social of all classes.
It should also be noted however, that AFK gaming is against the user agreement of virtually all MMORPG and can result in a player's account being banned.