Users on YouTube HD Verified networks should expect smooth playback most of the time
when watching high-definition YouTube videos (720p and above).
Users on networks rated as Standard Definition should expect smooth playback on
standard-definition YouTube videos (360p) and may experience occasional interruptions
on high-definition YouTube videos (720p and above).
Users on networks rated as Lower Definition may experience fuzzy picture quality and
frequent interruptions while playing YouTube videos at 360p and above.