Google this week announced news that YouTube videos watched on mobile devices will soon be able to be saved for offline viewing for up to 48 hours. The company's announcement left out some useful details. Luckily, Google has offered a bit more in an email sent to its YouTube partners (that is, people on YouTube that are making money) on Thursday. 

When the feature launches in November, the YouTube mobile apps will be updated with an “add to device” button for videos and playlists. The offline content will be accessible, when the internet connection drops out, through a designated area of the app. Viewers will have 48 hours hours to watch the videos. After the 48 hours, the viewer won't be able to watch it again until reconnected with the internet. 

Speaking directly to its partners, Google says in-stream ads will run in connection with the offline content. When a video is saved, the ads will come with it. Additionally, views will be added to the total view count once a user comes back online.

The real kicker will be that not all videos will be able to be saved offline. The feature is enabled by default for partners, however: if they don't want their content to be downloaded for 48 hours on to viewers devices they can disable it.

We have to ask: since partners will still be seeing ad hits, why wouldn't they keep the feature enabled? We suspect record companies and Vevo may opt-out of the functionality for music videos, as offline viewing doesn't yet fall under Google's rumoured upcoming YouTube streaming service. 

Google on the other hand doesn't want its for-purchase content to be accessed offline. It told partners that videos for rental or purchase will not be included in this functionality.

The company has yet to provide a solid date for the launch of offline viewing within YouTube, though says we can expect it sometime in November.