http://www.theregister.co.uk/2014/05/18/bitcoin_user_stoned_on_virus_warnings/

Sure, it was only the signature of "Stoned" but...

Bomb instructions, Holocaust denial, gay propaganda, Islam jokes,.............could also be implemented into the Blockchain. Also encoded.

That could mean the prohibition of the Blockchain itself.
(Possession, dissemination of prohibited content....)