Coming up: peer to peer chat (tox.im), hidden services (tor), distributed social networking, yadayada.. dont see how you can stop this, unless you turn off the power grid.
To prevent smartasses from using servers in countries without these restrictions, you further force ISPs to prevent any large amounts of data from being uploaded to those countries (cumulative, to avoid tricks like uploading small parts to many servers). E.g. back in the early 00s, some of our ISPs used to have different traffic caps for national vs international connections, here in Portugal.
It's not that hard if you're willing to go the full mile.