I once had this silly idea to create distributed storage of arbitrary data by exploiting a range of completely unrelated sites. Say, when you want to upload your file to the System, it may store one encrypted chunk as an image on a free image hosting site, another chunk as an encoded blog post on a random forum about farming (or in the user profile?), another chunk as a youtube video, etc. Imagine having something like hundreds or thousands of such "backends". Every chunk would be stored in 3 places for high durability of course. Free storage, hidden in plain sight :) Although, I didn't think through how to store the index reliably, and, because a moderator on a random farmers' site may delete our record(s), there needs to be a system which continously validates the integrity and reuploads the chunks.

Maybe such a silly project already exists?