Mobile as an advertising medium

This is a subject that I'll be blogging about more.
The concept is this: ad agencies and brands find it harder and harder to reach their audience. There are dozens of digital tv and radio channels. New magazines appear each week yet people get their entertainment and socialise through YouTube and MySpace. The point is that there is no mass media for advertising anymore.
The one thing that everone owns, and has with them most of the time is a mobile phone. There is a massive potential for these devices to be a channel through which information, entertainment and advertising can be sent.
When I say advertising onto mobile, I'm not talking about spam texts. As with spam mail, sending unwanted messages is not going to benefit brands. Fortunately because there is a cost to sending a message there is a limit to SMS spam, and the return would have to be pretty high.
When I talk about advertising to mobile, I'm talking about the kind of opt-in messages that will benefit the consumer in the form of useful information or offers. The advantage for the advertiser is that they are using the most powerful 1 to 1 marketing available. The mobile phone is the thing that most people have with them most of the time. To be able to get their attention through a mobile device is extremely powerful.