What's the use-case? o.o I can see geohash being used to further lock down where a posted image was from by applying it to the post - but what is "r" ment to do exactly?
Discussion
R allows apps to follow urls. So, when users post with a url, it can be searched by it.
The question is about prefixes. If I am interested in amethyst.social, i can follow it. But I want to follow all possible amethyst.social/* addresses.
Same for Geohashes