Microsoft's efforts to build out the app ecosystem for Windows Phone 8 appear to be reaching a plateau. Buried in today's announcement of the Nokia Lumia 928 for Verizon was the fact that the Windows Phone Store now has 145,000 apps, up only slightly from the 120,000 apps announced in October. The figures suggest momentum has slowed after the Windows Phone catalog doubled in size over the first half of last year. And it raises the question of whether developers are shying away from a platform that is still struggling to catch on in North America.

Microsoft has won over some high-profile developers this year, attracting new or redesigned apps from YouTube, Hulu, and Foursquare. The company says that the vast majority of the most popular apps on other platforms are available on Windows Phone. Microsoft has even developed Android software that will scan your phone, match the apps available on Windows Phone, and save them to your Microsoft ID to help you switch.

Some have made the case that Microsoft is smart to focus on quality apps over sheer numbers, even as iOS has passed 800,000 apps. Nokia recently resorted to a public campaign in an effort to get Facebook to build Instagram for Windows Phone. But so far, it hasn't been successful — and the broader campaign to get developers to build for Windows Phone appears to be having similar results.