With regards to filters to screen porn, it's difficult to implement at a national level; a number of countries have tried to restrict social media (Turkey, China) and some try to prevent VPN to another country (e.g. Dubai, Saudi) and non are 100% successful. I worked in Saudi for a short time and could VPN to my home country to stream movies - something they were trying to prevent.
What I thought interesting and see working was this:
"But these measures target an industry that's already marginalized in various ways—for instance, payment processors often discriminate against porn producers and distributors. "The more government interference in an industry... the more likely acquirers and banks will want to avoid transacting with it to avoid any reputation risk,"
My bank has blocked these types of payments previously leading to a embarrassing conversation!
Recently a number of NSA tools were released showing the increased level of national hacking activities and capabilities which sites like this need to guard against