Web: the unpredictable payoffs

People are wired to compulsively seek unpredictable payoffs like those doled out on the Web….Email and social media have the same reward structure as that of a casino slot machine: Most of it is junk, but every so often, you hit the jackpot — in the case of the Internet, a tidbit of juicy gossip or a heartfelt email, Stafford said.

source: businessinsider.com