Way back when, when I was trying to decide on what cellular service provider to choose, my two main concerns were coverage and ability to send SMS message abroad. I looked at Verizon, but they did not have text messages back then (from what I remember), I looked at sprint, but they could not send mobile email (aka SMS back then) to non sprint phones. I found a company called omnipoint - a GSM carrier, the only one back then in my area. I went with GSM since I could send SMS abroad. It later turned out that the networks that I was text messaging were GSM, so this might have been the reason for compatibility.

Text messages back then cost 10 cents to send, 10 to receive. It did not matter if they were domestic, or international - just 10 cents!
After a number of acquisitions (omnipoint --> voicestream ---> T-mobile), text messaging became 15 cents to send to international locations, and still 10 to receive! This meant that if you had a a 'bucket' of SMS messages, it was useless for sending international SMS!

When I switched to cingular, outgoing international SMS were 20c per message, 10c incoming (or 0c if you had a bucket). Now it is rumored that sending international SMS will cost 25c and receiving will cost 15c. WTF??? I am not charged extra for sending international emails, why am I charged more for international SMS? This is highway robbery! Unfortunately, carriers around the world have decided that it is profitable to charge these fees, so they do it. Unbelievable!