Literature has examined the adoption and diffusion of household computers and the Internet, or the first-order “digital divide”. However, the second-order “digital divide”, i.e., the specific usages of these tools, has received much less attention. This paper examines how the critical mass and diffusion channels affect the adoption of household computer applications, thus contributing to our understanding of this important issue. We propose that critical mass has strong effects on the adoption of both general and specialized computer applications, and diffusions from various channels, such as workplaces and schools, are significant. In addition, we argue that critical mass has stronger influence on general applications in early stage of the diffusion process while exerts stronger impact on specialized applications in late stage. In contrast, diffusions from workplaces and schools are generally stronger in late stage rather than in early stage. The stage-wise analysis using Current Population Survey data confirm our propositions.