Are there any integrations that would be willing to give me a tour of yours? Or have video of it?
1. What use cases were you satisfying?
2. How did it interact with other fields/notes fields or records? Could you OOTB map it to each of those (fields, Notes records) Any @mentions, etc work?
3. How was it organized or what was the object schema like Notebook>Notes for Objects>Records or was it Object>Notes per (Object or Account)