Text Messages are expensive because...

...uh... well... It must be because of the scarcity of bandwidth, right? After all, more cell phones means less lines available, right? Right?

But text messages are not just tiny; they are also free riders, tucked into what’s called a control channel, space reserved for operation of the wireless network.

That’s why a message is so limited in length: it must not exceed the length of the message used for internal communication between tower and handset to set up a call. The channel uses space whether or not a text message is inserted.

Professor Keshav said that once a carrier invests in the centralized storage equipment — storing a terabyte now costs only $100 and is dropping — and the staff to maintain it, its costs are basically covered. “Operating costs are relatively insensitive to volume,” he said. “It doesn’t cost the carrier much more to transmit a hundred million messages than a million.”

It is bad news for cell phone companies that the NYTimes has up an exposé on text messaging and the unreasonable rates that most cell carriers are charging. Is this perhaps why Apple has resisted advertising much about its own text messaging plans for the iPhone, and instead focusses on e-mail?