Yes, have read it and disagree. The act of syncing (sharing, backup, versioning, access) has to be super easy to use (i.e. tied to the OS). The problem with syncing apps in the past was they were hard to use so people stuck with their USB drives, emailing themselves, etc. Dropbox comes to mind as a syncing app that has made it easy to use.

Similarly, mp3 players weren't killer products until iPod came along :)