Working on two machines I find that the changes (adds,deletes) are not propagated across the network on NAS Drives (Iomega StorCenter using smb/cifs protocol and probably running some flavor of Linux all it says is GPL) and picked up by DO while drives attached directly to either machine via USB do appear to work properly. So in this example I have added a folder on machine 2 called "Z New Folder" then went to Machine 1 and deleted the directory and finally returned to Machine 2 to see if the change had occurred but the "Z New Directory" exists until I hit refresh.
I have the source code and it does seem to include a module called inotify which from what I understand is responsible for notification of directory and file updates. I haven't actually checked to see if it's on by default or needs configured. It also has a module dnotify (which was supposedly deprecated). I'll have to look more closely at what your link to the post requires for determining if it's functioning.