theodp writes: Microsoft's Antoine Leblond previewed the Windows Store at a developer event Tuesday, calling the new app marketplace that will be included in Windows 8 'the most significant developer opportunity ever'. 'This is where Windows shines, and where the opportunity for you as a developer is completely unprecedented,' he said. 'Every iPhone, iPad, Android phone, Android tablet and Mac sold in the last two years, I could combine all of these numbers together — it doesn’t match what Windows has sold.' And, if you're lucky enough to hit one out of the park with your app, Microsoft will let you pocket 80% of the take after the first $25k in sales, versus the 70% offered by Apple. Ready to drink the Kool-Aid? Enter Microsoft's Windows 8 First Apps Contest for a shot at having one of the first apps in the Windows Store when it opens for business in February.