Mandalay Digital Group Inc. announced on Thursday the acquisition of technologies developed by a German firm that facilitates app purchases by cell phone users. Mandalay, which has offices on the Cahuenga Pass, acquired an app search engine and “contextual advertising” technologies from Xyo, a Berlin-based startup. Mandalay provides programs for wireless carriers to help them monetize mobile content. The company’s main platform, called Digital Turbine, allows phone users to buy songs, ringtones, apps and other content. The Xyo search engine will be immediately incorporated into Digital Turbine, which is now in use by T-Mobile USA and about to launch with Verizon and Vodafone Australia. Xyo has existing deals with Deutsche Telekom Europe and Vodafone that bring Digital Turbine to those carriers. “There is a huge consumer appetite for finding and recommending the right app at the right time, versus wading through thousands of apps in the app store,” said Bill Stone, chief executive of Digital Turbine, in a statement. “This presents a significant opportunity for us.” Financial details of the transaction were not disclosed. Shares of Mandalay closed down 9 cents, or 2 percent, to $4.19 on the Nasdaq.