Myth #1: The mobile web is all about teenagers and twentysomethings.

Reality
Active users of wireless devices actually run the gamut of age groups, from pre-teens to senior citizens. For example, recent demographic surveys by Dynamic Logic and InsightExpress have shown that there are attractive numbers of wireless users in the 35-and-up age cohort. Smart marketers recognize that there are diverse and extensive audiences to be reached on mobile devices.

Myth #2: Because it's a medium that people use when they're "on the go," advertisers should be willing to pay extra for wireless' higher value, compared with other media.

Reality
Wireless has a higher value for certain brands at certain times. For other brands and other times, it doesn't. Advertisers are commonly asked for higher CPMs on wireless. Yet, if they do their homework, they will find the extra cost is not always justified. Like other media, mobile offers the discerning advertiser both high- and low-CPM opportunities. Advertisers should understand that serving an ad to a consumer in a supermarket at the moment they're choosing between competing products can be a very high value opportunity for one or more of the brands in that consumer's consideration set. But showing the same ad to that same person at another time or place, such as when they are considering brands or products that don't compete with yours, provides a relatively low-value opportunity.

John Hadl is managing partner and founder of BrandinHand, a mobile advertising agency with clients that include P&G and American Express.