This comment on the piece aptly sums up my response, it's by Sean Tucker:
Adam, I don't know you -- I came here from the Buzzfeed article criticizing the ethics of the study that linked to this post, but it appears we do have a friend in common.
I just have to ask - you honestly had a hypothesis that amounted to 'perhaps we can make people more depressed,' and decided to test it on a group that hadn't consented to the experiment, with no way to track its impact on their actual lives, only on the language they used in their Facebook posts? And you ask us to trust that this passed an internal review so it's ethical?
Please take a moment to step back and consider that. That appears to have been the train of thought that led to this.
That's appalling. Completely appalling. The Atlantic piece is right -- there's absolutely no way this passes APA deceptive research standards.
Beyond that, you'll never know what impact this actually had on depressed people. You can only measure what they posted to Facebook, which isn't a particularly meaningful or realistic indicator of their emotional state.
If this passed an internal review board, that's only proof that Facebook's internal review standards aren't what they need to be.
You're in a position of extraordinary power, with access to more subscribers than any other field study in history, a larger population than most nations, and subject only to how you review yourselves. You could deceive yourself into believing you have informed consent because everyone clicked 'accept' on the Terms of Service years ago, but there's no way even you think that's a meaningful standard.
I trust you're a reasonable person who doesn't set out to cross ethical boundaries. But on this one, I think Facebook needs to admit it did and make some changes. This study was unethical by any reasonable standard. There's nothing wrong with admitting that and figuring out a way to do better.
There's a lot wrong with going ahead with anything like this, ever again.