G.W.Furnas T.K.Landauer L.M.Gomez S.T.Dumais The vocabulary problem in human-system communication Commun. ACM ACM 30 964–971 1987 In almost all computer applications, users must enter correct words for the desired objects or actions. For success without extensive training, or in first-tries for new targets, the system must recognize terms that will be chosen spontaneously. We studied spontaneous word choice for objects in five application-related domains, and found the variability to be surprisingly large. In every case two people favored the same term with probability <0.20. Simulations show how this fundamental property of language limits the success of various design methodologies for vocabulary-driven interaction. For example, the popular approach in which access is via one designer's favorite single word will result in 80-90 percent failure rates in many common situations. An optimal strategy, unlimited aliasing, is derived and shown to be capable of several-fold improvements. FrankAllanHansen Ubiquitous annotation systems: technologies and challenges Proceedings of the seventeenth conference on Hypertext and hypermedia ACM Press 121-132 2006 Ubiquitous annotation systems allow users to annotate physical places, objects, and persons with digital information. Especially in the field of location based information systems much work has been done to implement adaptive and context-aware systems, but few efforts have focused on the general requirements for linking information to objects in both physical and digital space. This paper surveys annotation techniques from open hypermedia systems, Web based annotation systems, and mobile and augmented reality systems to illustrate different approaches to four central challenges ubiquitous annotation systems have to deal with: anchoring, structuring, presentation, and authoring. Through a number of examples each challenge is discussed and HyCon, a context-aware hypermedia framework developed at the University of Aarhus, Denmark, is used to illustrate an integrated approach to ubiquitous annotations. Finally, a taxonomy of annotation systems is presented. The taxonomy can be used both to categorize system based on the way they present annotations and to choose the right technology for interfacing with annotations when implementing new systems. AdamMathes Folksonomies &#x2013; Cooperative Classification and Communication Through Shared Metadata 2004 GeneSmith Tagging: People-powered Metadata for the Social Web (Voices That Matter) New Riders Press 1 2008 PeiJiunTan DaveClarke Audience-centric taxonomy: using taxonomies to support heterogeneous user communities Dublin Core Metadata Initiative 123–127 2007 JingtaoWang JohnCanny End-user place annotation on mobile devices: a comparative study CHI '06 extended abstracts on Human factors in computing systems ACM Press 1493-1498 2006 Advances in Location-Based Services (LBS) are opening opportunities for using the location of people, places, and things to augment or streamline interaction. While computers work with physical locations like latitude and longitude directly, people usually think and speak in terms of places, which adds personal, environmental and social meaning to a location. To address this conceptual mismatch, location-aware applications must incorporate the notion of place to achieve their full potential. In this paper, we investigate four techniques for collecting end-user place annotations interactively using cell phones. The results from a usability study suggest that while all the four methods receive similar preference ratings in understandability, the "photo memo plus offline editing" method is the most favorite approach in ease of use. In addition, users indicated their desire to adopt more than one place annotation method in location-aware applications.