— Google (@google) September 29, 2015
What are these features? Well, let's go through them in the order that Google did. First, there's album sharing. More than one user can share an album, and when any adds a photo to the collection, others will receive a notification.
Then there's people labeling. You can assign names to the faces that appear in your photos. These names are private, so if you want to call someone Dutch Thunder, go right ahead.
Then there's Chromecast support. Think of this feature more as a triumphant return. Google+ Photos had Chromecast support prior to becoming Google Photos, and now it's back.
Google says people have uploaded more than 50 billion photos and videos since the service launched.