ine and offline modes. These games are played through either the service provider's or a third-party game provider's Web site. For offline gaming, the games can be downloaded. This category encompasses the widest range of games, including individual and multi- player games, network games, offline games, and arcade games. Of the three categories, downloadable games are the most popular approach today, largely due to the creative and rich multimedia content, appealing presentation, and lower cost compared with SMS games. Very importantly, these games play like conventional handheld games. Downloadable games are very attractive in their format, permitting animation and the ability to be played offline. They can also be played similar to the tradi- tional retail model: The user pays once and can play offline as long as he or she likes. But in order to support downloadable games, new technologies are required that allow a game program to be transmitted over a wireless network and to be understood and run on a mobile device. In addition, the devices need to be able to handle a greater range of features, such as graphics, sound, larger screen sizes, improved user interfaces, security, and, of course, digital rights management (i.e., content security). Mobile Game Platforms Various technologies are now available to develop downloadable games, including Java ME (formerly Java 2 Micro Edition [J2ME]), BREW (Binary Runtime for Wire- less), ExEn (Execution Environment), and Mophun. The most widely adopted technology is Java ME, which is used worldwide. However, competing technologies are increasingly being used, with varying degrees of market penetration. BREW is used in the United States, China, Taiwan, and Korea; ExEn is found in France Germany; and Mophun is popular in parts of Scandinavia. Java ME Sun's (www.sun.com) Java ME runs on top of a virtual machine, an extra layer of software that serves as a barrier of protection from malicious or erroneous soft- ware. A key advantage is that the virtual machine allows the Java