If you travel around Europe you will see all the towers that Romans used to carry messages. Lots of them, specially in places like Spain or Greece with lots of mountains. In other places like most of France such a tower is far less useful as there are less differences in height.
Those towers were already being used before Romans took them, for example in the North of Spain they would be used to alert from Viking Invasions from sea, it will alert the "Castros". We are talking centuries before the Romans.
About complex messages being transmitted far away, look at the Silbo Gomero at the Canary Islands, it was used before the Spanish conquered the Islands in XVI century(we don't really now how much older than that was, but probably centuries):
http://www.youtube.com/watch?v=qlZh9I1pxj0
for example in the North of Spain they would be used to alert from Viking Invasions from sea, it will alert the "Castros". We are talking centuries before the Romans.
... except the Vikings were well after the end of the Roman empire.
That's very interesting (especially the whistling language). I suppose what divides Roman watch towers from the Internet (from my POV) is that they could only carry a fixed messages. They weren't able to send general communications.
That said - the geography aspect is not to be overlooked.
If you travel around Europe you will see all the towers that Romans used to carry messages. Lots of them, specially in places like Spain or Greece with lots of mountains. In other places like most of France such a tower is far less useful as there are less differences in height.
Those towers were already being used before Romans took them, for example in the North of Spain they would be used to alert from Viking Invasions from sea, it will alert the "Castros". We are talking centuries before the Romans.
About complex messages being transmitted far away, look at the Silbo Gomero at the Canary Islands, it was used before the Spanish conquered the Islands in XVI century(we don't really now how much older than that was, but probably centuries): http://www.youtube.com/watch?v=qlZh9I1pxj0