@Grant837, let me try to reiterate the request here. The best technical way to describe this feature request is to parallel it to how anchor tags work on a webpage. Now if the reader has never developed a basic webpage, this description will not make sense, but since most developers of the Evernote product likely have, I'm hopeful this will be helpful to them.
My feature request would allow the following.
A user can put a link into any part of an Evernote document.
A user can put an "anchor" into any location of an Evernote document. For instance, the user may have a 10-page Evernote document containing a term they have defined somewhere else. They could place an "anchor" (or whatever Evernote decides to call these) at that term definition so the inserted link described above would take the user to that anchor location.
A link should follow the same web usability standards and be represented with an underline. Hovering over the link would provide a popup with details about where the link would take them. It might also provide a short summary of the words where the anchor is located, thus negating the need to click the link unless greater detail is needed.
This is the easiest way I know how to describe this feature. Model the functionality after the way the web and HTML have been performing this identical functionality for the past 25 years.