Windows Phone Marketplace, the software portal from where Windows Phone 7 handset owners can download applications for their new devices, has managed to add some 1,000 more items during the past two weeks, now offering over 6k apps for purchase and download. In all fairness, it does not come too much as a surprise that the number of applications in the Marketplace grew over 6,000 (you can check on them here), since Microsoft confirmed last week that the portal sees a growth rate of around 500 apps per week. However, it is quite impressive to see that Windows Phone 7, the new mobile platform Microsoft brought to the market in October 2010, enjoys such popularity among mobile application developers. A few days before 2010 was over, some two months following the official launch of the first Windows Phone 7 devices, the Marketplace housed 5k applications, up 4,000 since October. The number of developers who registered their interest in deploying new software for the Windows Phone Marketplace grew as well, and Microsoft confirmed last week that the community already has over 20,000 members. Undoubtedly, the number of apps added to the Marketplace would steadily grow to over 10,000 in about two months from now (provided that the app additions remains at the same level), while being on track to leave RIM's BlackBerry App World behind before mid-2011. Considering the fact that the number of developers interested in Windows Phone 7 is increasing, chances are that the number of apps being added each month to the marketplace would grow even faster. Microsoft is certainly investing a great deal of resources in making sure that more software is included in the Marketplace, so that more users would choose Windows Phone 7 over other platforms out there. Of course, the Windows Phone Marketplace still has a long way to go before proving a real competitor to Apple's App Store or to the Android Market, but the first steps in this direction were already taken.