The plugin I have longed for: the remembrance agent - based off of the work of Thad Starner at MIT in the 90’s. I’ll post the link to the paper below but the idea is this:
The Remembrance Agent (RA) is a program which augments human memory by displaying a list of documents which might be relevant to the user’s current context. Unlike most information retrieval systems, the RA runs continuously without user intervention. Its unobtrusive interface allows a user to pursue or ignore the RA’s suggestions as desired.
tl;dr You have a panel that is constantly performing searches on the words and phrases you are typing or reviewing, and updating to show the most relevant results. Clicking on a result would insert it into the current document at the cursor.
This casts a wider net for potentially relevant documents that you might not be aware of enough to think to link to. Ideally there would be options to change search refresh rate, runs different search algorithms or alter them, etc.
I highly recommend the paper, it’s an interesting read: http://alumni.media.mit.edu/~rhodes/Papers/remembrance.html
I wouldn’t know how to make something like this. So I am posting it here in hopes that someone else thinks it’s a cool enough idea that they want to whip it up.