I've been doing the same, but on a very small scale. Mostly sending a funny episode of some show to a group of friends or occasionally sending a movie to my folks. I don't doubt that if I was mass distributing these files it would attract attention.
Also, wouldn't breaking the hash nullify one of the ostensible advantages of this method (the de-dupe of the stored files)? If the goal is solving global file distribution, making each copy of every originally-identical file unique - and therefore requiring n times the storage - isn't a viable solution.