Related to previous posts, another dead technology: the Semantic Web. The mention of JSON-LD and Schema.org was pretty much what I thought would be the culmination (and it was.)

Another way the faint shadow of Semantic Web lived on in an interestingly weird facet of the web: the HTML living spec still has a section on microdata which I could swear I thought obsolete, but, even though it's effectively become useless from the implementers' standpoint, it's still there.

Though it's possible to argue that it shouldn't have been a part of the core HTML spec anyway, and instead have worked more like microformats did—be beside the spec, not within it. But I guess it's a simple enough part that it doesn't hurt to have it in there, and a tiny library can fill out the void left behind by the browser API removal.