In reply to KevinHodgson.

My two favorite thinkers lately in the areas of niche communities/interests and topics like discovery within those spaces are Kicks Condor and Brad Enslen. They're doing an excellent job of thinking out how some of the old web communities and spaces might fit into a broader IndieWeb perspective. Ideas like polyphrenia certainly help to expand such a conversation.
Incidentally, Nate, Hypothesis and the functionality and value it provides me, make it one of the few polyphrenetic sites that I not only don't mind working within, but actually enjoy working within, despite my all-in stance on owning all of my own data. It certainly helps that it solves some very specific problems, but it also does so in an ethical and trustworthy way (business-perspective wise) that also allows me to also own my data if I wish. I do sometimes worry what it and its community would look like if it were used at the same scale that Twitter were--sometimes scale brings unforseen problems.