For any Americans thinking 'well, at least this doesn't affect me as a natural born citizen', you should be aware that one of the most common principles applied to visa and passport control activity by countries is 'reciprocity'. That is, countries look at how the US treats their citizens at the American port of entry, and turn around and apply that same standard to Americans.

So the next time you turn up at the Canadian border and are asked to produce your facebook account details... this is why.