It's going to be very interesting to see where all the tabletop gaming people land. G+ got a lot of pickup in that hobby because the early API blended tools, like Hangouts with overlays and easily segmented discussion groups, that worked well with online tabletop gaming. Roll20 integrated well with G+ (at least until Google killed the Hangouts API in April 2017).
The early adopters reached enough of a critical mass that others used it solely because of who was already there, making it an actual social network for at least that purpose.
Much like when Reader folded, G+'s critical mass is going to spread out to a half-dozen other places and refragment. And like Reader's exit, there's a vacuum right now for someone to jump in with something better and charge a nominal amount for it.
The early adopters reached enough of a critical mass that others used it solely because of who was already there, making it an actual social network for at least that purpose.
Much like when Reader folded, G+'s critical mass is going to spread out to a half-dozen other places and refragment. And like Reader's exit, there's a vacuum right now for someone to jump in with something better and charge a nominal amount for it.