As mobile devices become increasingly pervasive and commonly equipped with short-range radio capabilities, we observe that it might be possible to build a network based only on pair-wise contact of users. By using user mobility as a network transport mechanism, devices can intelligently route latency-insensitive packets using power-efficient short-range radio. Such a network could provide communication capability where no network infrastructure exists, or extend the reach of established infrastructure. To collect user mobility data, we ran two user studies by giving instrumented PDA devices to groups of students to carry for several weeks. We evaluate our work by providing empirical data that suggests that it is possible to make intelligent routing decisions based on only pair-wise contact, without previous knowledge of the mobility model or location information.