After disasters (or to minimize expensive data use generally, and take advantage of available Wi-Fi), bypassing the cell network is useful. But it's not something that handset makers bake into their phones. colinneagle writes with information on a project that tries to sidestep a dependence on the cellular carriers, if there is Wi-Fi near enough for at least some users: "The Smart Phone Ad-Hoc Networks (SPAN) project reconfigures the onboard Wi-Fi chip of a smartphone to act as a Wi-Fi router with other nearby similarly configured smartphones, creating an ad-hoc mesh network. These smartphones can then communicate with one another without an operational carrier network. SPAN intercepts all communications at the Global Handset Proxy so applications such as VoIP, Twitter, email etc., work normally."