Avatar history stretches back to the early 1970s, when two guys at NASA - Steve Colley and Howard Palmer - invented a multiplayer game called MazeWar.

They played with other early computer users over the ARPANET, a precursor to the Internet developed by the Department of Defense and a group of universities.

At first, players moving through the maze were represented by words or numbers. But computer and avatar historian Bruce Damer gives the honor of first avatar to a graphical eyeball that moved through the maze with its cyclops gaze pointed in the direction it moved - or at the other players it was about to shoot.

"That was definitely an avatar, no question about it," said Damer, chief executive officer of Digital Space Commons and author of the book Avatars! Exploring and Building Virtual Worlds on the Internet.

In the 1980s, computers began spreading into ordinary homes. There were several computer networks that they could hook into, communicating only with computers on the same network. Chip Morningstar and Randy Farmer, who worked at Lucas Films, invented a virtual world called Habitat with a Commodore 64 computer. Users assembled cartoonlike avatars by selecting from a menu of heads and bodies. They could then walk around a digital space and talk to one another, their words appearing in chat bubbles over their heads.

But it wasn't until the 1990s, when the various computer networks came together to form the Internet, that the avatar phenomenon really took off, Damer said. Many multiplayer games and virtual social spaces were created, but few survived because they made no money. As they folded, Damer said, many declared this type of virtual reality dead.

But Phillip Rosedale, CEO and founder of Linden Labs, had a different take, Damer said. "His feeling was it was too early. You still had most people using dial-ups," which are too slow for many virtual-world applications.

He was right. In 2003, Linden Labs launched Second Life, which in turn launched many new industries based on selling goods and services to virtual-world inhabitants.

- Kellie Patrick