Will Wright, creator of The Sims, the game in which players manage the lives of simulated humans, noticed that hackers began to modify his game as soon as it was released in 1999, creating mods (or patches, as they're also called) that would, for example, render all the characters nude. "If you look at the amount of stuff fans have created for the game," says Wright, "it probably outnumbers the stuff we've created, 9 to 1. I think it's great." Diabolically, Wright introduced his own mod to The Sims in 2000, a wee Trojan horse in the shape of a guinea pig. If not properly cared for, the rodent spread a deadly virus to its owner, a plot twist that Wright did not disclose until many characters were in their virtual graves.

Mods are a fad, just like the internet.