The Symbian Foundation is a non-profit company -- majority-owned by Nokia -- that develops the eponymous and still most widely used mobile operating system in the world. Williams was with the foundation for more than 10 years, according to Mobile Magazine. He will be replaced by Tim Holbrow, the company's CFO until now.

While Williams wasn't directly employed by the Nokia Corporation, its majority ownership in Symbian and the fact that it employs the open-source OS in most of its mobile devices means that the shakeup will certainly affect the Finnish telecom company. It's starting to become tough to count on one hand how many top-level executives have left in just the last two months. Most recently, Ari Jaaksi, the VP in charge of Nokia's Meego Devices resigned just two weeks ago. Before that, Nokia's CEO was replaced with a Microsoft executive, prompting Nokia's head of N-Series to quit (for reportedly being snubbed to take the top spot). 

Regardless, Symbian is still selling quite well internationally. A report in August put Symbian's worldwide daily sales figures at 300,000 -- 50% more than the 200,000 Google CEO Eric Schmidt claimed Android was selling. Still, Nokia and Symbian are losing in the U.S. market, to the likes of Apple, and, particularly Android. We'll see what moves Nokia makes to try to recapture the lucrative market now that much of the old guard has been replaced.