I’d think we’re missing one important folder with shareable bookmarks. I’d call it Bookmarks Exchange Folder which is needed exclusively to send out a bookmark to another entity, be that person, corp or alliance.
What details it could have? Make it possible to Create Contract for a bookmark by right click on it in People and Places window. Contracts could use usual contracts terms and options but no operating with bookmark like item.
Player1 creates contract for bookmark, Player2 buys it but bookmark received goes in the Exchange Folder. It would function like Item Deliviery on upwell structures (where you can only receive the item) but functions just like it is long transition from one to another bookmark folder.