Blackberry maker RIM says that it has been taken aback by the speed with which teenagers have adopted the BlackBerry as the phone of choice. 

The handset has become popular with teenagers due to the Blackberry Messenger (BBM) instant messaging application. Earlier today, in an interview with Mobile Marketing, Mike Kirkup, director, developer relations at RIM said: “The speed and scale with which that transition happened has been amazing, in terms of the uptake figures.”

Kirkup reiterated the point during a panel session at tonight’s Mobile Mondays event, admitting that the company had not set out a strategy to target the youth market, and telling delegates: “People are just walking into stores asking for BBM.”

The development has created a challenge for Blackberry to market itself to two very different demographics, but Kirkup says this is no big deal for the company, noting that the company has always targeted business and consumer users with very different marketing messages.