According to YouTube’s Help section, Offline viewing will be coming to a mobile device near you from next month. The new functionality will allow users to watch video content for a short period of time, even when an Internet connection is unavailable.
Users will still be able to watch the videos that they’ve added to their device for a limited period of up to 48 hours. If the device is offline for more than 48 hours the content cannot be viewed offline until the device reconnects. Once connected, the offline window refreshes and the viewer is able to watch the content again.
From the watch page through the functionality, viewers will be able to designate certain content that they can watch for a short period of time when they do not have connectivity. At the time when the user no longer has connectivity, they will be able to watch these videos and playlists through an “on device” section of their guide.
I certainly see many advantages to this for people who travel and loose connectivity or spend the day in a building that the radio waves can’t penetrate. Once you are connected to a good network you’ll be able to create a playlist for the day to view whenever you want.
One down side though is that it looks like un-skippable Ads will have a permanent presence in offline clips.