service

Users increasingly interact with a heterogeneous collection of computing devices. The applications that users employ on those devices, however, still largely provide user experiences that assume the use of a single computer. This failure is due in part to the difficulty of creating user experiences that span multiple devices, particularly the need to manage identifying, connecting to, and communicating with other devices. In this paper we present an infrastructure based on instant messaging that simplifies adding that additional functionality to applications. Our infrastructure elevates device ownership to a first class property, allowing developers to provide functionality that spans personal devices without writing code to manage users' devices or establish connections among them. It also provides simple mechanisms for applications to send information, events, or commands between a user's devices. We demonstrate the effectiveness of our infrastructure by presenting a set of sample applications built with it and a user study demonstrating that developers new to the infrastructure can implement all of the cross-device functionality for three applications in, on average, less than two and a half hours.

Source-code examples of APIs enable developers to quickly gain a gestalt understanding of a library's functionality, and they support organically creating applications by incrementally modifying a functional starting point. As an increasing number of web sites provide APIs, significantlatent value lies in connecting the complementary representations between site and service - in essence, enabling sites themselves to be the example corpus. We introduce d.mix, a tool for creating web mashups that leverages this site-to-service correspondence. With d.mix, users browse annotated web sites and select elements to sample. d.mix's sampling mechanism generates the underlying service calls that yield those elements. This code can be edited, executed, and shared in d.mix's wiki-based hosting environment. This sampling approach leverages pre-existing web sites as example sets and supports fluid composition and modification of examples. An initial study with eight participants found d.mix to enable rapid experimentation, and suggested avenues for improving its annotation mechanism.