Though of course some people really do still rely on RSS readers, stubbornly adding an RSS feed to your blog, even in 2019, is a political statement. That little tangerine bubble has become a wistful symbol of defiance against a centralized web increasingly controlled by a handful of corporations, a web that hardly resembles the syndicated web of Werbach’s imagining.
So if we are asking ourselves why RSS is no longer popular, a good first-order explanation is that social networks supplanted it. If we ask ourselves why social networks were able to supplant it, then the answer may be that the people trying to make RSS succeed faced a problem much harder than, say, building Facebook. As Dornfest wrote to the Syndication mailing list at one point, “currently it’s the politics far more than the serialization that’s far from simple.”
Motherboard has an excellent history of RSS, and the drama that unfolded as its creators fought for the right to define the protocol and map out its future.