Not every app is available everywhere. For example, of the nearly 71,000 apps in the Marketplace, 59,687 can be downloaded in the U.S., 57,000 in the U.K., 54.399 in France and 52,346 in India. If the quality of apps can be determined by the number of times an app is rated, than the quality of the inventory in the Marketplace is getting better. Looking at the UK marketplace, 8.5% of the listed apps have been rated 5 or more times compared with 6.6% 6 weeks ago.
The largest category of apps in the Windows Marketplace are "Entertainment" apps with 18% of the total followed by "Tools/Productivity" at 14%, "Games" at 13% and "Books and Reference" at 12%. The top four make up 47% of apps in the Windows Marketplace. A vast majority of apps in the online store, 65%, are free while 24% require you to buy them. The remaining 11% are paid apps with a free trial.
For the Windows Marketplace to become a challenger to the Android Market and the App Store, there will need to be more acceptance of the platform overall by smartphone buyers. Back in late 2009, before it was launched, no one could have predicted the impact the Motorola DROID would have on the Android OS and thus the Android Market. That type of dramatic impact in a handset is what Windows Phone needs.
source: AAWP via WMPoweruser