In recent decades, with the rapid progress of Information and Communications Technology (ICT), the impact of informatization on the social operation and human life is deepening. Based on the level of digitalization, networking and intelligentization, we review the history of informatization, and propose that the development stage after digital twin will be digital intelligence and digital transcendence. As informatization is becoming the key driving force of network evolution in the future, we put forword 4 characteristics for the future network, namely network-computing collaboration, access collaboration, photo-electric cooperation and network intelligentization, and emphasize the key role and challenge of optical communication.