Favourites only puts it in Dropbox's cache. You still have to manually "export" it if you want it in a particular location on the SD card. The desktop client

Favourites only puts it in Dropbox's cache. You still have to manually "export" it if you want it in a particular location on the SD card. The desktop client allows you to choose which directories you want to sync. Being able to do that would go most of the way towards being more useful for Android. (There was a votebox issue when I last looked.)