Campus Media Group is targeting college students with ads and special offers via mobile phones, Media Life reports (via Media BuyerPlanner). To date, 3 million students have opted to receive the ads on their cell phones. "It's an effective way to reach students in a time-sensitive way," said Joel Eisfelder, media director. "It makes it easier to get in front of students on the go, using a medium they like to use."

Messages consist of text, images, audio or video. A text message can be up to 160 characters or 30-40 words. They can be used with other forms of direct-response advertising like billboards, TV, internet and newspapers. The calls are used to promote contests, coupons and announcements, and are only sent to the student once. "Some see it as too intrusive to use it regularly," Eisfelder said. "So we don't want to overdo it."

Students opt in through their wireless providers to receive messages. The number of messages sent is limited to four per month. "About 20 percent forward the message to a friend," said marketing director Jason Bakker.