Mobile, ubiquitous, social, and cloud computing have brought an unprecedented amount of information, digitized resources, and computational power—spanning many different devices—to users today. Correspondingly, an increasing amount of work and leisure activity is taking place in this distributed digital computing environment. For example, in a hospital, the medical record and bio-signals of patients are digitized and accessed by multiple stationary, mobile, and wearable devices. At home, digital and social media, email, photo libraries, and the like are accessed on a wide range of devices including laptops, smartphones, TV sets, and other Internet-connected appliances. However, this rapid increase in the diversity and volume of both computational devices and digital content quickly introduces corresponding organizational challenges, leading to digital clutter. Many people feel overwhelmed and burdened by organizing and retrieving their digital resources, which includes handling, organizing, and finding information—a problem commonly referred to as information overload. Moreover, handling multiple and often concurrent tasks while coordinating with other individuals adds an additional level of complexity.
Despite the overwhelming success of new devices and cloud-based information-sharing infrastructures, the evolution of the user interface models that people use to interact with these innovations and the representations with which they organize electronic information on these platforms has not kept pace. Although it is much more common today for users to access information through the browser or on a mobile device than in the past, most contemporary user interface models are still fundamentally grounded in the personal computer metaphor, as part of which electronic resources are defined by the applications used to manipulate them and "filed" using a desktop metaphor (files, folders, and application windows). This application- and document-centric model leads to a fragmentation of a person's information. For example, information related to a specific work project is often scattered across multiple files, local folders, cloud folders, and across different applications such as email, instant messaging, local and cloud-based document editors, Web browsers, and social media channels/communities. Moreover, this information might be scattered across different devices and accessed by multiple users.