I am grateful to one of my former graduate students who is from Estonia, who first made me aware earlier this year that Estonia had chosen to "close" its Internet border to many international gambling sites. Here's one report of the closing in a casino trade paper.
The method of border enforcement chosen by Estonia is (I believe) the shape of things to come in most countries around the world, because it is less cost-intensive than building and operating a national network gateway.
Estonia has (I am told) issued an order to domestic ISP's demanding that these ISP's block traffic to sites listed by the regulator. I imagine that this type of enforcement system will develop into an automated procedure, where a regulator authorised under domestic state law could enter a given web site address into a national "block file" which then reflects automatically to servers run by all local ISP's.
Here's a question for the network-mavens among us: are there any RFC's currently circulating that would help both to enable and standardise this sort of border enforcement? (That is, a border enforcement protocol that is otherwise content-agnostic: waiting for an instruction set on what to block.) If not, I think there will be. Sovereign states will probably appreciate the opportunity to standardise some border enforcement protocols.
Lesson for network protocol engineers of tomorrow: here's a career opportunity waiting to happen.