How is shouting threats on Twitter fundamentally different than calling the airport or going there and shouting the same words there? I don't think it would be

How is shouting threats on Twitter fundamentally different than calling the airport or going there and shouting the same words there? I don't think it would be OK if I emailed TechCrunch and threatened to kill them all if they don't stop their blogging within a week. And if the police comes call it a joke.