film is just one component of a story that you start telling before your first festival showing... and continue to build on and embroider even after you've released the DVD and digital download. The "movie release date" becomes just one milestone in this conversation between you and your audience. Some people who participate in the conversation may never actually buy a ticket or a download... while others may become so engaged that they buy everything you offer, and help market your movie to everyone they know.
This is two things:
1) utilizing the power of the internet to be different media all at once.
2) This is branding. Intellectual property building.
Filmmakers and novelists and other creatives need to figure this out now. Their book, comic, movie, animation, music, radio drama, is only the beginning. A book isn't just between the covers. A movie isn't just onscreen.
Don't think small. Think about how you can add to your creation. How you can translate it. How it can have further value - both to you and your audience