https://en.wikipedia.org/wiki/OFFSystem
Basically people would be hosting random-looking blocks of data, but users could be instructed to XOR two carefully chosen blocks together, producing a meaningful file.
Because of the nature of XOR, if Alice sees that Bob is hosting a file F, she could generate and host a file G, such that F XOR G produces a banned file, providing plausible deniability for Bob (as long as he can point to a file H such that F XOR H produces an innocent file).
https://news.ycombinator.com/item?id=16617136
Thus, it would be better (if it could be afforded --- see some of the other comments on cost estimates) to continue there, or perhaps one of the other altcoins that's already in use for monetary purposes.
For a popular blockchain like teh bitcoin, it would cost quite a lot to introduce much data.
That’s a pretty awesome Kickstarter project.