Originally Posted by
Ditto
Netflix shows on the show page that it is going to be removed in "Month, Year" so you know it in advance.
It actually does sync up, I've seen some episodes offline on my phone and then watched online from my laptop and had no issue finding where I stopped.
It hasn't worked for me even once. I watch the episodes on my iPad or iPhone and then try to continue on Xfinity or Apple TV and it doesn't see any of the progress.