[caption id="attachment_5822" align="aligncenter" width="618"] One of roughly a million-billion ads for Microsoft's Surface tablet.[/caption] Microsoft dumped untold amounts of cash into marketing its Surface tablet. Enormous displays in New York City’s Times Square, 30-second spots on “The Walking Dead,” and endless subway and bus ads don’t come cheap, you know. But has all that money and attention actually translated into a blockbuster product, at least at this early stage? In an interview with Le Parisien (and subsequently reported by a number of publications, including the Chicago Tribune), Microsoft CEO Steve Ballmer confessed that the Surface RT has sold “modestly” in its first few weeks of release. He added that roughly 4 million Windows 8 upgrades had sold within three days of the next-generation operating system’s launch. The 10.6-inch Surface tablet features a built-in kickstand and a flexible cover that doubles as a keyboard, allowing it to double as a laptop. The version currently on the market runs Windows RT, a version of Windows 8 designed for the ARM-based processors that currently dominate the tablet market; a version running Windows 8 Pro and powered by a third-generation Intel Core processor is due in January. Microsoft is building the Surface’s hardware and software in-house, a radical departure for a company that usually licenses its software to third-party hardware manufacturers. The device is an integral part of Microsoft’s evolution toward becoming a self-described “devices and services” firm: as Ballmer wrote in his most recent shareholder letter, the company will focus increasingly on “developing new form factors that have increasingly natural ways to use them including touch, gestures and speech.” If one takes those words at face value, it seems that Surface is a harbinger of the company’s future direction. But that means Surface will also need to sell well in order to justify that strategy. While it’s still early innings—remember, the version of Surface running “regular” Windows 8 hasn’t even been released yet—modest sales could prove a worrisome sign for Microsoft.