Also: Facebook is a very incomplete and often inaccurate view of our lives. I assume that most regular users create their Facebook timeline as an idealized, curated mental facsimile of their lives, filtering out real inadequacies, exaggerating stories that might make them look more wealthy, busy, free, etc.

Perhaps they're accounting for this but I'm not really a fan of doing social science based on a data set that's more fantasy than scientific measurement.