Data & Society community members wrote individually about “Experimental evidence of massive-scale emotional contagion through social networks” (PNAS 2014 111 (24) 8788-8790) and the public controversy surrounding the study. Their comments are collected here:

danah boyd, What does the Facebook experiment teach us?

Kate Crawford, The Test We Can—and Should—Run on Facebook

Ed Felten, Facebook’s Emotional Manipulation Study: When Ethical Worlds Collide; Privacy Implications of Social Media Manipulation; and On the Ethics of A/B Testing

Tarleton Gillespie, Facebook’s algorithm — why our assumptions are wrong, and our concerns are right

Micah Sifry, Why Facebook’s ‘Voter Megaphone’ Is the Real Manipulation to Worry About

Anthony Townsend, The Ethics of Experimentation in the IoT

Janet Vertesi, The Real Reason You Should Be Worried About That Facebook Experiment

(Updated October 23, 2014.)