Korea has one of the most advanced information infrastructure in the world. The issue of internet or cyberspace addiction came along with the advancement of high-speed internet and personal computers a decade ago. Internet addiction, once introduced humorously as webaholism, has now become one of the most important adolescent behavioral problems including sex, drug and other delinquent behaviors. Boosted by PC-room and innovative online game industries, the adverse effect of online game overuse now overwhelms other media including video game, online chatting, and cyberporn. Teenagers tend to prefer interactive media such as internet, mobile and peer-to-peer communications to classical uni-directional media such as T.V. and newspaper. The age of initial exposure to these media gets younger. Social and medical support network to remedy the problems does not seem to catch up with the rapidly evolving internet and game industry. The highly addictive and pervasive nature of role-playing and recent casual games are discussed, along with the medico-social and legislative efforts in need from the government, communities, schools and families.