Sustainability should be viewed with great concern in order to reap the benefits of any innovation. Sustainability of internet usage is very crucial for the Internet to have an impact on the life of users. This book therefore provides a new knowledge on determining sustainability of Internet usage. The main objective of the work is to determine sustainability of internet usage and the variables which have effects on sustainability of internet usage. The work is based on a model derived from diffusion of innovation theory, i.e. the innovation decision process model, by Rogers (2003). The findings of this work showed that communication channels, interpersonal and social network and perceived and realized benefits have significant positive effects on sustainability of Internet usage, while security concerns and interruptions have significant negative effects. The findings should help shed some lights on determining sustainability of usage of an innovation, especially the internet. This work should be especially useful for academicians and students interested in the new media (internet)and people responsible for ICT programs for bridging the digital divide.