Microsoft’s Windows Marketplace app store now has more than 40,000 apps on its books, reports All About Windows Phone. This compares to more than 500,000 seen on Apple’s much more established App Store. During its first year, Windows Marketplace has grown steadily, passing the 30,000 apps mark in August. All About Windows Phone expects more than 50,000 apps by January as 165 new apps – 68 percent of which are free – are being added each day.