@queentakesking wrote a post a while back on what would be needed to decentralize Tumblr, essentially turning it from a service with a single provider into a protocol with many implementations. I’m not sure how I didn’t realize it when the proposal was first posted, but a lot of the desired functionality already exists in some interoperable fashion. Reblogs, in particular, could be implemented in part with trackbacks, which Movable Type first introduced ten years ago and have since made their way to WordPress and a lot of other self-hosted blogging software; this would handle the essential functionality of pinging authors. Quoting the original text is harder, given that there’s no standard way of indicating a post’s actual content in an HTML page, but it isn’t an intractable problem, and should at least be trivial for reblogs between users of the same service. Similarly, following other users is largely a solved problem given that RSS exists. Essentially, if you want a look at what a decentralized Tumblr might entail, take a look at the blogosphere circa… oh, 2006.