Jesus that's cheap. Anyone know how good their differential syncing is, or what they are using (librsync?) Are they using inotify or is it a regular tree walk?
(Fires up a decompiler) Let's check...
1. From a quick glance I can't find anything related to patching in backend or change handling classes. Either I'm missing something or it doesn't handle arbitrary changes well. There's some suspect-driving long ByteDelta property on Change class, but I fail to see where it's used in a meaningful manner.
2. It uses a lightweight abstraction over System.IO.FileSystemWatcher. This means inotify, when ran on Mono on GNU/Linux.
http://en.wikipedia.org/wiki/IFolder
The project structure is completely different, so it's probably not even inspired by iFolder.