Mobile carriers are beginning to use advertising in their services, after years of cautious consideration. Vodafone (NYSE: VOD) Spain has announce plans to insert dynamic and interactive ads into its Live portal, and is calling the initiative the Mobile Marketing Discover Program. Ten brands have signed up, including Heineken, Nestle, Atrapalo.com and Linea Directa. Amobee is running the ad service, and there are plans to offer ad-funded mobile gaming, TV, video and messaging. In the US, regional carrier Revol has completed a mobile advertising trial of 5,000 people which achieved engagement rates of almost half, it has decided to go ahead with the service. Revol trialed an idle ad system, which showed ads, weather information, sports scores or local information on the phone’s idle screen which users can click on, reports RCR Wireless. “According to Jon Jackson, CEO of Mobile Posse, the trial achieved total engagement rates of around 45 percent. Around 15 percent of participants clicked on an ad while it appeared on the screen, and another 30 percent accessed it later.” The service is provided by Mobile Posse, and Revol plans to offer discounts of $20-60 on the cost of a handset to get people to sign up.