Microsoft has officially confirmed the earlier information that they will change the name of the App store for Windows Phone platform from Windows Phone Marketplace to Windows Phone Store. This is not a surprise as the company tries to reconcile the names of their products and the official App Store for Windows 8 is called Windows Store.
Along with the new name, there are some improvements in the app search, now done with the help of Bing (it will correct any errors in the spelling of your search terms). The company is now making changes in the lists of popular and new applications. You can check the new improvements already available @ Windowsphone.com