You just forgot you wrote it down.
Every note you've ever written knew something you've since forgotten. That offhand thought from March. The question that kept you up in November. The thing you noticed but never followed up on. All of it sitting in a list somewhere, buried under everything that came after.
NoteReturn brings them back. Every time you write a new note, you get an old one in return. Something you wrote weeks or months ago, showing up when you least expect it.
Why random?
The best ideas show up sideways. A note you wrote about a conversation suddenly maps onto a problem you're solving today. An old question resurfaces, and this time you have the answer. A throwaway observation turns out to be the start of something.
Your notes are full of things worth revisiting. They just need a reason to come back around.
Write a thought, get one back. The more you put in, the more interesting the returns.