Back in the days of Friendster, I thought "Enemyster" would be a nice feature for social networking sites. In addition to selecting your friends, also select your enemies. The system can then recommend connections between people who hate the same people :)<p>The idea came up when I met someone who referred to a girl (whom he had met recently at a party) as "selfish" and "irresponsible". He didn't know that was my ex, and he apologized profusely when I mentioned it.<p>I told him not to sweat it... he's clearly a good judge of character (as it took me three years to figure those things out). It wasn't a lasting friendship, but it was good for a few beers...