SMS is an absolute goldmine for telephone companies: Just think about it. In Norway you pay about 70 øre (i.e 0,70 kroner) per SMS Text message. A text message has about 160 bytes of information. That is 4,37 Kroner (or about UK£ 0,33 or about US$ 0,63) per kilobyte.

I believe GSM traffic (and speech) goes with 9600 bps (Bytes per Second). 9600 bps = 9.6 kbps = 576 kbpm

If the price of telephony was the same as the price for SMS, you would pay roughly 2500 kroner (UK£ 200 / US$ 280) per minute to talk using your cell phone.