The worldwide mobile advertising market will be worth more than $12 billion by 2011, Gartner forecasts, but cautions that carriers must be careful if they want to get a piece of the pie, especially since well-established players such as Nokia (NYSE: NOK), Google (NSDQ: GOOG), Yahoo (NSDQ: YHOO), MySpace and Microsoft (NSDQ: MSFT) are all pursuing the mobile revenue opportunity as well. King-Yew Foong, a Gartner research director, said operators should take advantage of their position, and use SMS and MMS, email, mobile search, location-based services to deliver targeted advertising messages, while at the same time regulating spam and a user’s privacy. The report also found that they have to convince advertisers and marketers of how they are different from the internet search giants such as Google, Yahoo and Microsoft, and other traditional advertising mediums, such as newspapers and TV. The report concludes that right now, carriers are not credible players, but they can successfully leverage their relationships with customers, knowledge of local markets, extensive customer databases, network control and multiple channel access. Release.