Imagine a world without the Interthingy
What on earth would terrorist and spies do then?
Perhaps they could use old fasioned telephones, dead letter boxes, use a cell system, actually talk to someone, microdots, snail mail or shipping such as DHL and FedEx to name just a few.
The dumb terrorists are the ones we know about, the smart ones are already using secure fieldcraft and probably don't rely on the internet for anything really sensitive.