In Turkey, currently twitter and youtube are both censored, but not pornhub , youporn and the such:
http://en.rsf.org/turkey-youtube-blo...014,46050.html
And: "There is no technical problem at our end. Internet users who modify their DNS settings or use VPNs are the only ones in Turkey who can now access YouTube.".
In fact, in several european countries the ISPs are removing the domain names of unlicensed gambling sites since many years, still everyone learned how to change DNS into google or other full DNS.
Let UK force ISPs to blacklist non-compliant pornhub's at some time, UK people may soon learn to change DNS, I guess.