Good news - when you create a video on Magisto, it is set as private by default. Nobody can discover or view your video unless you choose to share the link or add it to a public album.
Every album aside from your "My timeline" album is private. Note that if you place a video in the "My timeline" album it will be public.
We give our users the control that they need: want to share a private album? No problem, you can easily do that as well if you wish!