I would not be surprised in the future to see a lot of countries attempt to ban foreign social networks. Basically, with Facebook, Twitter, and LinkedIn, the US government has defacto access to a treasure trove of who knows who, who influences who, and want skills everyone has. This information would be very expensive to collect by intelligence services, but with these US companies, is just handed on a platter.
Basically, if you are a geopolitical rival of the US, you would have to be a fool to allow your people to use these American services.
Well there's another school of thought: if you want to be a significant world power (prerequisite to being geopolitical rival to USA) you have to let your citizens read whatever they want, vote however they want, and join what the fuck ever social network they want.
Basically, if you are a geopolitical rival of the US, you would have to be a fool to allow your people to use these American services.