I take quite a lot of notes across hundreds of PDFs, and it can sometimes be difficult to remember where I took a particular note, or to view all of my notes and annotations quickly.
It would be quite useful to have a global notes database where I can view all the notes and annotations I have made in MarginNote, and sort/filter them by hashtags, documents, keywords, date created, etc.
This is a feature found in Qualitative Data Analysis (QDA) software like NVivo, MaxQDA, and Atlas.ti, but those programmes are not nearly as convenient when it comes to highlighting PDFs. If MarginNote had an effective system for accessing your entire database of Notes, that would make it the ultimate piece of database software.