So, were you ever reading this huge 300-pages specification heavily cross-referencing itself, jumping around and getting a headache when looking for the place where you stopped reading the last time?
Were you doing something similar in C code, but praising vi for document marks?
ELinks can do them, too! For vim non-users:
When you place a "document mark" (just "mark" from now on), you place an _invisible_ anchor at the current position in the document. You can place several such marks --- each mark is identified by a single character (any reasonable character will do). Then, you can just happily browse around aimlessly (but see below) and when in the same document again, you can return to any of the marks in the file again. That will restore your position in the file at the time of placing the mark.
You can place a mark by the "m" key followed by the mark character. You can go to a mark by the "'" (apostrophe) key followed by the mark character. E.g., you can place a mark named "a" in the file by pressing "ma", then return to it anytime later by typing "'a". You can of course change those shortcuts at any time to anything you wish in the keybindings manager.
Short summary: you can place a mark (e.g. z) in a document by pressing "mz" and then go back to it anytime later by pressing "'z".