While most of our attention in the mobile world is focused on smartphones, there’s a massive opportunity for any company that can take over so-called developing markets, i.e. places where people are still mostly using relatively simple “feature phones.”

Taking another stab at that space is Nokia, which is unveiling the colorful Asha 501, a Asha-running touchscreen phone that comes with the features of a smartphone but the $99 price of a feature phone. The device isn’t particularly flashy: Nokia’s only given it a three-inch 320 x 240 display, 2G (!) radio, and a camera without a flash —  so this is by no means a particularly high-end device.

The other, plausibly more important thing, about the Asha 501 is that it’s not running Windows Phone, which is potentially bad for Microsoft for two reasons. One, it makes it very clear that Nokia is still hesitant to invest all its resources in Windows Phone, and, two, it shows that Nokia still can’t create a cheap phone that also matches the minimum hardware requirements for Windows Phone. (Phones running Windows Phone 7 need to have displays with a resolution of at least 480 x 320, for example.)

Neither reality is great for Microsoft, because while the high-end smartphone market is cutthroat and brutal, the market for low-end smartphones in developing markets is wide open, at least for now. While Mozilla and Nokia are making some big moves in this area, Microsoft is still being left out of it.