In a recent case study released by Microsoft Advertising, a Windows Phone 7 app developer, Richard Foster, has been said to have earned $28,882 in just 4 months, using Microsoft’s Advertising SDK for Windows Phone. Now it may not be the runaway success that Rovio had with Angry Birds, but it shows that developers on the WP7 platform can make a living too. Foster has released 14 free apps, all ad-supported, on the Windows Marketplace – a change of pace from the paid apps he used to develop for Widows Mobile 6x previously. This also shows that there is a demand for apps, no matter how simple, like unit convertors on the marketplace. Granted, not every developer will see the same amount of success, but it’s a good start and should encourage more people to join the platform.