Yahoo is closing the doors on its popular Go service, which was active on over 400 phones across multiple carriers. The service will officially shut down on Jan. 12, 2010.

According to Cory Pforzheimer, senior manager of public relations at Yahoo!, the service had reached an evolutionary dead end. "Go was a great success for us, but if you look where mobile has come and where it's going, it just doesn't make sense anymore," Pforzheimer said.

Yahoo! will be sending out an e-mail to users of the service today, which will alert them to the change. According to Pforzheimer, high-end smartphone users still will be able to download dedicated apps to their phones, but he said that feature phone users will be better served by Yahoo!'s mobile site. He cited improvements in mobile browser technology as a big reason that the mobile Web version of the site has surpassed Go in functionality. Go was launched in 2006. 

While not sure of the exact numbers, Pforzheimer said that Go, which offered users simple access to Yahoo! services such as mail, messaging and news, was downloaded tens of millions of times.

Meanwhile, Pfrozheimer said that Yahoo! will continue to focus on developing more sophisticated and intriguing mobile apps. He said that Yahoo!'s latest Fantasy Football app, which focuses on a very specific and passionate audience, has proved a huge success, and one the company aims to repeat.