The Windows Phone Marketplace has hit the 20,000 App mark, and in record time too. The first 10000 Apps took four and a half months, but the second 10000 as taken only a further two and a half. Compare that to RIM who have only just over 20’000 Apps now after over 2 years and the growth rate is even more impressive.
Of course the more mainstream WP7 becomes, the risk increases that the quality of the Apps being added goes down. Microsoft needs to ensure that the App submission and Approval process is firm and doesn’t allow a flood of irrelevant apps, or worse, spam/trojan apps, to become commonplace within the Market.
Source: Windows Phone Applist