Next week's EU data protection "safe harbour" decision may require exactly that: Facebook may no longer be allowed to export personal data from the EU.
Edit: data protection would also have a huge effect on the "peeple" app, discussion of which seems to be banned on HN.
Nobody should be allowed to export personal data from such jurisdictions except for the owners of that data themselves. A U.S.-ian should be allowed to decide to trust their personal data to a company inside E.U. jurisdiction but that company shouldn't be allowed to trade that data anywhere else (especially, back to the U.S.). Of course, that's a complete pipe dream, and I'm just hallucinating.
I imagine that would only apply to sites which store PII[1]. The database should be located under the same jurisdiction (which doesn't mean every country, since some will have treaties to allow exporting to certain places (EU for example)) as the person whose data it is, and the data should not be transferred through other jurisdictions.
Well, pretty much any website stores an email, name and password. Every startup would need to look at all the bilateral treaties between every major country in the world. This is simply impractical.
Edit: data protection would also have a huge effect on the "peeple" app, discussion of which seems to be banned on HN.