That's an interesting idea. It can certainly be useful to be able to add and go back to notes as one works on a project. Fill out the form so we can log it and assign a case number for you and don't forget to vote for it.
Please describe in more detail so the developers understand how it might differ than Markers for example. How are they attached? What might be their features? How are they displayed?
If you can do a mock-up screenshot that might help.
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