The 2012 analysis is interesting- thanks for providing a link to that. Also, this kind of reminds me of Confirmation Bias (the tendency to interpret new evidence as confirmation of one’s existing beliefs or theories) in the way that it seems as if “friends” (meaning online followers/ friends) tend to adopt each other’s moods maybe not as much because they actually feel that way and maybe more because they are seeing that everyone else feels that way and it is confirming that this is the mood of the moment.

Interesting read, thanks!