RIM stock plungesShares of Blackberry-maker Research in Motion plummeted Friday morning despite the company having announced better-than-expected Q3 earnings yesterday. The company also announced a better cash position for the quarter as it is set to launch a marketing drive for two new phones on January 30.

However, in a conference call with investors and analysts, RIM chief executive Thorsten Heins said that the company’s service-revenue model would change significantly next year. Currently, RIM’s revenue is based on the service fees it charges customers for use of their proprietary network. This accounts for more than a third of RIM’s revenue. However, Heins did not specify the changes to revenue stream they were expecting, which has made the market nervous.