It's always fun to find that ideas we think are unique to our generation are in fact far older. For example, who invented hypertext?
Many might assert that it was Tim Berners-Lee, with his invention of the Web (1988). But while Sir Tim did (and continues to do) many wonderful things, the idea of hypertext greatly predates the Web.
Other common replies, at least among technologists, might be Ted Nelson, who in his book Literary Machines (1983) and his ambitious but ultimately unsuccessful Xanadu system pioneered many relevant ideas, and Doug Engelbart, who pioneered hypertext and many other things besides.
Historians of science are likely to cite Vannevar Bush's As We May Think (1945), which is notable as a description of a hypertext system that (essentially) predated computers, and influenced Nelson and Engelbart.
There are other precursors, but (getting to the punchline), I learned at a recent workshop of the work of the Belgian Paul Otlet, who from 1895 onwards described and built systems that (using cards, not computers) introduced ideas that (now quoting Wikipedia):
prefigured what ultimately became the World Wide Web. His vision of a great network of knowledge was centered on documents and included the notions of hyperlinks, search engines, remote access, and social networks. (Obviously these notions were described by different names.)
If he's in Wikipedia, he can't be that obscure (can he?), but this was all news to me.