The present invention enables a cell phone or PDA user to purchase a full version of an application with a single key stroke, without switching back and forth between the application and a browser. A one click upgrade is made available which is intuitive and quicker than prior methods known in the art....http://www.google.com.hk/patents/US20050055309?utm_source=gb-gplus-share專利 US20050055309 - Method and apparatus for a one click upgrade for mobile applications
