Two separate things made me think of starting this thread...
The first was an instance here on Dogs when someone made reference to the fact that posters should not be discussing an ongoing criminal trial. To which Stoo answered that it didn't matter, the site is hosted in the USA.
The second is the case of two British racists who were prosecuted in the UK for things they posted on an American website. The catch is that in the USA their postings were protected by the 1rst amendment and no law had been broken. Did the activity happen in the UK (where the postings originated and were illegal) or the USA (where the postings actually exist and were legal)?
It's an odd subject where logic, law, and technology get it on in a freaky threesome.