Yaron posted an article on why he chose LinkedIn over Orkut, when he decided to only use one personal-connections site. My reasons for choosing only Orkut and not LinkedIn -- although for the same basic reason that I can only handle upkeep on one, not two -- are much more frivolous. Basically, Orkut looked more fun, sleeker, and more experimental. Since I use these services for a while until I get bored and then stop visiting, I look for a transitory entertainment value rather than a long-term career or business advantage.