There has been little understanding of how consumers adopt and use the mobile Internet. This dissertation seeks to bridge this gap in prior literature by focusing on consumers’ cross-platform consumption behavior on mobile devices. The first study of this dissertation addresses how the adoption of mobile applications influences the use of corresponding mobile websites. Pseudo-panel analysis based on repeated cross-sectional data suggests that the introduction of a mobile app by a major national media company leads to a significant increase in demand at the corresponding mobile news website. In addition, it reports that this effect is greater for consumers with higher appreciation for concentrated news content, with stronger propensity for a particular political viewpoint, and with fewer time constraints. The results are consistent with the interpretation that adoption of a provider’s news app stimulates corresponding mobile news website visits. The second study of this dissertation examines whether the quality of local fixed-line Internet service influences mobile Internet adoption and usage. An empirical analysis shows that local fixed-line Internet speed relates negatively to mobile Internet adoption and usage; if the local fixed-line connection is insufficient, consumers tend to get online through their mobile phones. Further, better local mobile Internet speed increases the likelihood of adopting and using the mobile Internet. Neither fixed-line nor mobile Internet speed has significant impacts on mobile-specific offline services such as taking photos or videos. In some circumstances, competition between the two platforms is stronger, such as among younger consumers and those living in areas with lower fixed-line Internet speeds.