It's hard to imagine the Bernie Sanders campaign growing like it did, without people posting on Facebook about him and his ideas.
#1 point of exposure for me -- was seeing things my friends posted on FB.
Vernor Vinge drew up some diagrams of what this would look like, whereabouts 2005: http://vrinimi.org/front9uns.j...
I'd be interested in seeing a paper that estimates the maximum lifetime of a technological civilization, on the basis that : (A) the estimates given are right about the number of stars, how many habitable planets are in the goldilocks zone, etc.,., (B) we are not atypical, and then (C) that we have not encountered signals from any radio emitting civilizations.
We might find that there would be so many technological civilizations, that technological civilizations should only exist for a few dozen years. Or we may find that they are so rare, that it's extremely uncommon that they overlap, and they may well last for several millennium.
Earth is a beta site.