Thanks to @TRBruce for linking to Bob DuCharme’s  An older post of Bob’s, “A 19th Century Linking Application,” describes Shepard’s — lists of court decisions (and statutes), each listing cases that have cited them.  Back links, like Wikipedia’s “What links here.”  With a semantic marker for questioned, overruled, followed, etc.  “Triples.”  These were originally stickers (the ancestor of Post-Its?), then nice fat sets of red books (there was something great about the feel of them), then online.

Bob’s article is a good read, thought-inspiring and an excellent context in which lawyers can think about “in-line” vs “out-of-line” linking.  (Different than out-of-line thinking.)

I would have liked to have seen a bit of discussion of the long-standing forward-linking system, one case citing another by the (media-bound) system of 5 U.S. 137 (1803)  ( volume series page (year) ).  These links are the technical embodiment of the notion of precedent.  (The notation, though bound to the idea of “books” of decisions, exerts influence from it’s grave.)