People can be knights or bandits

In the guise of these alter egos, players can move around Ultima's vast world of 32,000 screens, 20 major cities, 9 shrines, 9 dungeons and vast uncharted frontiers.

Within this beautifully illustrated, tremendously interactive online universe, players band together to create tribes, professional guilds and armies. Over time, they build up cities and territories, each with its own moral code.

Murder most foul

And they also kill each other. Murdering other characters has become the central goal of so many players that there is literally war between the good guys - players who enjoy banding together to build online civlization - and the bad guys - barbarians who take pleasure in their murder and mayhem.

Ultima Online: A matter of life or death?

But sometimes things can go too far. A few months back, a hacker broke into a spinoff from Ultima called Diablo II.

He entered the game's operating system and gave himself superpowers that allowed him to dominate whole areas, destroying and killing all who stood in his way.

Whether this kind of action breaks the rules of online gaming or is actually an advanced form of gamesmanship sparked intense controversy among the tens of thousands of Ultima players.

Interestingly, the massacre has also sprouted another internet phenomenon.

Traumatised by their virtual assassinations, many Diablo players banded together for group therapy sessions - online, of course.

It shows how seriously the players take their online existence, blurring the lines between fantasy and reality.