Certainly it's disturbing that social media sites allow researchers to manipulate us. But what's even more disturbing is that some of these scientists (such as Jeffrey T. Hancock, co-author of the infamous Facebook study in which the posts of 700,000 non-consenting users were manipulated to see how this affected their emotions) now seem to want to pretend that the relative ease with which research can be conducted on the internet has given rise to a brand new ethical dilemma: is it permissible to conduct research on unwitting internet users? (see Vindu Goel's NYT article, 8/13/14)
In Goel's article, Hancock is quoted as saying, "I liken it a little bit to when chemistry got the microscope." Well, sure, and it's fine to deceive and manipulate microorganisms in a petri dish, as far as that goes. But that doesn't explain why Hancock would be so baffled at the outrage that followed the disclosure of his study. Humans are not microorganisms, and the invention of social media sites does not mean that our society's core moral values have changed in some way that now makes it permissible for human beings to be deceived and manipulated.
In other words, the ethics of scientific research remain unchanged: you still need to get the subject's informed consent. This involves giving the subject the answers to such questions as: what are the possible side effects? (Of the 700,000 involved in the Facebook study, presumably at least a few of them developed symptoms such as anxiety, depression, suicidal ideation, etc.); what legal rights are the subjects giving up?; what is the purpose of the study?; and, will the results of the experiment be freely disseminated, as legitimate scientific research is supposed to be, or will the results be available only to a select few corporate or government officials?
Of course, knowing the answers to such questions will influence the proposed subject's decision as to whether or not to participate. And that's apparently what some researchers don't like. But then again, they never have liked this aspect of human-based research. It's inconvenient. It makes things much harder on them. And that's as it should be. We wouldn't allow researchers to slip a drug in the water supply for an entire city of 700,000 people in order to study its effects on their emotions.