Dropbox.js - official support for JavaScript Dropbox apps

Beyond the obvious benefit (as stated in the blog) for developers not needing code for db access, authentication, and the overhead of deployment, such apps can bring trust to a different level.

We can now have apps that store data in a location controlled by us users. Dropbox will need to support finer levels of folder access with their authentication, as well as support for making sure the apps don't access other sites.