slightly off topic, but i was noticing a correlation between activity on linkedin and people quitting or changing jobs, it's been rather uncanny how correlated they have been (8 out of 8 folks that have left lately have been using linked in aggressively before departing) and this is in china, land of blocked sites (facebook, twitter, etc).

i'm wondering if there's data to be mined from other such sites so that you can make a prediction of who's quitting. i see this as a major privacy issue, i.e. as i'm a user of linked in and someone's trying to predict if i'm quitting my job.