OGame.org

Quoted

5. Nothing that is mainly used for ruining another person's account. This includes building destroying, research forgetting, blowing up someone’s planet and just about anything else.
OGame is played over months and years - not hours like most other games. In other games you can destroy a player's basic foundations, making him loose. In OGame, this would effectively bring a player's hard work of several months - sometimes a year or more! To nothing. One of the main aspects of OGame is that you can always rebuild. Some attacks would prove major setbacks, but you're never back to square one - you always have your planets/buildings/researches to help you rebuild.