Necro time, sorry! How many of the HandyNotes plugins are getting updated for Cataclysm? I pose the question with hope that previous authors are updating or coming back, or new authors are taking over.
About plugins: how do you import the data so it shows up on the map and minimap? I am using Mapster and Chinchilla currently. When I click on a mailbox, it adds a little envelope to both the WFM and MM, but wasn't the idea that all known mailboxes were added by default? Same with vendors, trainers, etc. In fact, the only things added by default are questgivers, and that probably is because I am using EveryQuest.
The only plugin I authored for HandyNotes, is HandyNotes_FlightMasters and I hardcoded a database of flightmaster locations in it.
All other plugins are made by their respective authors and I do not know if they intend to do anything with it for Cataclysm. For HandyNotes_Mailbox, the author decided not to supply any database and just left it to the user to collect mailbox locations as the player plays.