Someone posted an article here on HN once which talked about how peoples general dispositions was transmittable to people up to two or three degrees of separati

Someone posted an article here on HN once which talked about how peoples general dispositions was transmittable to people up to two or three degrees of separation from yourself. So if you're in a bad mood then that attitude can spread to your friends of friends of friends. Anyone else remember reading that article? I'd like to bookmark it.