It's also worth noting that this is not (contrary to Andreessen's disingenuous tweet) a case of a website accidentally tripping over scientific-ethics norms thr

It's also worth noting that this is not (contrary to Andreessen's disingenuous tweet) a case of a website accidentally tripping over scientific-ethics norms through its normal course of operations, unaware that what they're doing might be considered a psychology study. This was explicitly a psychology study, performed by professional psychologists, for the purpose of collecting data publishable in a journal! The lead author (and the Facebook employee on the project), A.D.I. Kramer, has a PhD in social psychology. I think it's perfectly reasonable in that setting to expect the researchers to be following the norms of scientific ethics.