If you are collaborating with others and using Dropbox as a DEVONthink sync location (never putting your database in a Dropbox or automatically cloud-synced folder), it is not possible to sync between Dropbox accounts. This means you need to have a shared account where everyone using the sync data will need to know the name and password to access it. This can create a problem because you would be giving everyone access to the whole account! But as one of the astute users, Frederiko, pointed out...