Ultraviolet is a platform that let's you keep your movies across multiple movie websites such as Vudu, Flixster, and a few other platforms from what I hear. Vudu is the only website I know that lets you share videos with others, up to 5 others. Vudu is completely legal and from what I can tell, owned by Walmart.
There are a few catches with Vudu though. First is you can only share with up to five people. Next, not entirely sure, but it's mostly for streaming videos. There is an option for downloading I've heard, but idk the specifics. Finally, you need to live in the United States to watch these movies.
My current movie collection:
The Passion of the Christ
Lord of the rings complete collection
Harry Potter 1-6 (missing 7 part 1 and 2)
X-Men 1 2 3
X-Men origins Wolverine
The incredible hulk
Be kind Rewind
Jurassic Park 3
A sound of thunder
There is a parental control option, although I don't know the specifics yet. If there are any movies you want blocked, let me know. I'll see what I can do