Some players have reported online spats leaking out of the game -- players have hacked into others' accounts, posed as acquaintances and spread rumors about real people through instant messaging. Some have even reported identity theft.

Piers Mathieson and his wife, Jennifer, are two more hardcore "Sims" players. They log several hours most days.

After the Las Vegas couple distributed photos of themselves to friends, one griefer hacked into Piers' America Online account and stole his in-game character's possessions. Someone else posed as Piers and told other players that Jennifer had died of cancer.

The Mathiesons may have been easy targets. Their character, Mia Wallace, was the most popular in Alphaville, as one of the game's servers, or cities, is known.

"You start having to question who your real friends are, who you can trust, who you can't trust," Jennifer Mathieson said. "It also paints a huge bulls-eye in your forehead."