OKCupid Experiments on Users Too
With recent news that Facebook altered users' feeds as part of a psychology experiment, OKCupid has jumped in and noted that they too have altered their algorithms and experimented with their users (some unintentional) and "if you use the Internet, you’re the subject of hundreds of experiments at any given time, on every site. That’s how websites work." Findings include that removing pictures from profiles resulted in deeper conversations, but as soon as the pictures returned appearance took over; personality ratings are highly correlated with appearance ratings (profiles with attractive pictures and no other information still scored as having a great personality); and that suggesting a bad match is a good match causes people to converse nearly as much as ideal matches would.
FB's experiment was to see if they could alter the mood of their user. OKC tried to see if they could get more conversations going. Intent matters. OKC's is fairly harmless. FB's experiment could have a ripple effect and cause negative consequences.