Ubiquitous computing is weaving itself into the fabric of our age, creating unique opportunities for accessing and sharing information regardless of time and location. Recent development in hardware technology paved the way to small and portable devices such as wireless sensors, PDAs, iPods, and leads to new generation of cell phones with computing capabilities which are called as smartphones. These smart devices enable location-aware applications as well as empower users to generate and access multimedia content anywhere.

Mobility information of cell phone users plays an important role in a wide range of smartphone applications, such as context-based search and advertising, early warning systems, traffic planning, route prediction, and air pollution exposure risk estimation.

However, the mobility information captured in the cell phone is low level data units and can not benefit these applications directly. In this thesis, we investigate the problem of enhancing smartphone applications by providing mobility information at suitable abstraction level. In particular, we adress the following problems: (1) In order to provide high level model of human mobility, we design and implement a complete framework, the Mobility Profiler, for discovering mobility profiles from raw cell based connection data. (2) In order to enable smartphone applications requiring personalized mobility information, we propose TRACK ME: A web based centralized middleware for building smartphone applications leveraging on top of location tracking and mobility profile construction systems. (3) In order to utilize location tracking capability and ubiquitous nature of smartphones for social collaboration, we design and implement a location based crowd-sourced sensing and collaboration system over Twitter. (4) For the developing regions and environment where connectivity occurs intermittently, we apply our findings related to human mobility for improving routing algorithms in Pocket Switched Networks (PSNs). Based on the regularity of human mobility profiles and of intercontact events, we propose PRO routing; mobility profile aware, decentralized, fast (low-delivery-latency) and efficient (low-message-overhead) routing protocol for PSNs.