Peter Davidson at BeConnected tells you at the end of his post on Trendwatching.
SMS(text messaging) while huge in other parts of the world has been slow to catch on in America. Cultural phenomenon like interactive TV programs i.e. American Idol have driven adoption and now even universities are building systems to use SMS to aid professors-student communications. If somebody uses SMS for years in school they are certainly open to it when they graduate and become your potential client.
How true. When I was in Sofia working with ExpoTeam a couple of years ago, SMS was already well established as a marketing tool to promote the Sofia Auto Show and Home Techno (Bulgaria's version of CES). "Teaser" text messages were sent to Sofia cellphone users with different incentives to get them to pick up an invitation form from any of the hundreds of available outlets in and around the city.
Of course where there's only one big cell carrier, that makes life easier. Still, there is a huge untapped marketing potential for SMS over here. With millions being trained to text message in order to vote for their American Idol, it shouldn't be long before we start accepting SMS as a marketing medium.