Way back when I kept a blog (Blogspot, I think), my posts would show a "linkback" at the bottom, linking to any other source that had linked to my post.
It would be cool to have something like for links from one note to another within Joplin.
For example, making a To Do list for the weekend. One item on my list is to create a meal plan for the upcoming week. I link to the meal plan on my To Do list -- it would be nice to see something (automatically) on the meal plan linking back to the To Do list.
EDIT: that's just one of many examples. 90% of my Joplin use right now is notes for the Penetration Testing with Kali Linux course -- I'm using links all over the place there, and it would be really useful to have this functionality! I'll be able to use these notes during the 24-hour exam, so I'm trying to be as thorough as possible so I can find what I need quickly.