My feeling, confirmed by some industry researchers, is that once you buy a really smart phone with a decent web experience, then you’ll want to have email on it. And instant messaging, like MSN and Skype, and all other social tools. The success of the iPhone and the diffusion of BlackBerry seems to indicate that some users of phones (professionals and big spenders, at least) are already browsing the web and checking their emails. Smart phones are being sold more than ‘dumb’ phones, meaning that in fairly short time there will be many terminals that support email and web+social apps. At that point sms/mms will be soooo old (and WAP is already soooo old now, I can’t believe somebody still mentions it as a media for advertising).
Besides, I believe that sms/mms simply too annoying and intrusive to be effective: to read an ad pushed through sms you have to react to the beep, and reach to the phone. Advertising on email is a whole different story because when you get the ad you’re already looking at the screen.
So maybe I’m wrong and it’s going to take many years still before we’ll say goodbye to SMS. Or the telecom operators are missing a huge opportunities, while Apple and Google and Nokia are getting ready to reducing them to dumb pipes (like the internet did for land lines).