In practice, the syncing was never reliable enough for most users, and different clients implement the standard differently. My hope was that it would eventually converge on something interoperable like CSS did, but I don't think there's enough usage for that to happen. And things are moving away from filesystem paradigms anyway (iOS, etc) so WebDAV is slowly becoming even less relevant.
I wonder if that's why iDisk went away. Wasn't it based on WebDAV?
But, you needed to set everything else up on your own. I built a system that filled in the gaps that was used to proof corporate documentation and clinical drug trial materials.
Worked great for years.