[nemothekid]

And what standards body has defined the metrics so that we can measure what a "poor job" is in this case? The comic still stands, Facebook could very well be doing a poor job now, and is that unethical? What if FB's input had no overall effect? Is the test still unethical even though no one was sad? How will we define what is and isn't unethical? If advertisements makes me sad, and FB experiments with placing more ads on my news feed, leading me to become depressed, is that unethical? Are they still intentionally doing a poor job even though they are probably more or less unaware of my disposition to ads?

I think Randall has a fair point here. FB has essentially been doing this for years and something about their latest test got all our panties in a bunch. Its clear though now, FB never had to adhere to any sort of standards for their website.

[DalekBaldwin]

Going further: what if this was broad exploratory study, not meant to test any specific hypothesis? What if they rated posts based on thousands of features, a parameter space large enough to guarantee they would find plenty of correlations (both spurious and substantial), and randomly perturbed each user's feed and monitored how the features of their contributions changed? I would expect that they already do this, and from the very small amount of detail I've seen in articles about the mood factor so far, I wouldn't be surprised if this was just one of the more interesting correlations that fell out of that sort of process.