I think there's some interesting research one could do on the virality of the photo you see below.
The sad fact is that my wife found this photo in her twitter feed because WIlliam Gibson tweeted a link to the flickr page. I searched for his name on Google+ and found him and was the first reshare, after that it spread quite nicely.
I suspect there's similar spread on Facebook, twitter retweets, flickr and other networks.
In any case I'm really enjoying following the ripples for this post and watching it spread throughout G+.
https://
#googplus