Our central claim is that user interactions with everyday productivity applications (e.g., word processors, Web browsers, etc.) provide rich contextual information that can be leveraged to support just-in-time access to task-relevant information. We discuss the requirements for such systems, and develop a general architecture for systems of this type. As evidence for our claim, we present Watson, a system which gathers contextual information in the form of the text of the document the user is manipulating in order to proactively retrieve documents from distributed information repositories. We close by describing the results of several experiments with Watson, which show it consistently provides useful information to its users.

In this paper, we introduce a class of systems called Information Management Assistants (IMAs). IMAs automatically discover related material on behalf of the user by serving as an intermediary between the user and information retrieval systems. IMAs observe users interact with everyday applications and then anticipate their information needs using a model of the task at hand. IMAs then automatically fulfill these needs using the text of the document the user is manipulating and a knowledge of how to form queries to traditional information retrieval systems (e.g., Internet search engines, abstract databases, etc.). IMAs automatically query information systems on behalf of users as well as provide an interface by which the user can pose queries explicitly. Because IMAs are aware of the user's task, they can augment their explicit query with terms representative of the context of this task. In this way, IMAs provide a framework for bringing implicit task context to bear on servicing expli...

In this paper we explore the problem of Caching of Search Engine Query Results in order to reduce the computing and I/O requirements needed to support the functionality of a search engine of the World-Wide Web. We study query traces from the EXCITE search engine and show that they have a significant amount of temporal locality: that is, a significant percentage of the queries have been submitted more than once by the same or a different user. Using trace-driven simulation we demonstrate that medium-size caches can hold the results of most of the frequently-submitted queries. Finally, we compare the effectiveness of static and dynamic caching and conclude that although dynamic caching can use large caches more effectively, static caching can perform better for (very) small caches. 1

Assistance in retrieving documents on the World Wide Web is provided either by search engines, through keyword-based queries, or by catalogues, which organize documents into hierarchical collections. Maintaining catalogues manually is becoming increasingly difficult, due to the sheer amount of material on the Web; it is thus becoming necessary to resort to techniques for the automatic classification of documents. Automatic classification is traditionally performed by extracting the information for representing a document (``indexing'') from the document itself. The paper describes the novel technique of categorization by context, which instead extracts useful information for classifying a document from the context where a URL referring to it appears. We present the results of experimenting with Theseus, a classifier that exploits this technique.

The placement of Websites in ranked retrieval and the viewing patterns of Web search engine users is a crucial issue for Web site owners and Web search engines. However, little large-scale research has examined the viewing patterns of users of commercial Web search engines. The research results reported here address three questions, which are: (1) How many pages of results do Web search engine users ’ examine? (2) How many Web documents do Web search engine users’ view when searching the Web?, and (3) How relevant are the Web documents that they are viewing? We present findings from large-scale research into the page viewing patterns of users of the FAST commercial Web search engine. Using data samples representing thousands of users, we examine common patterns concerning the number of pages of results viewed, the number of pages viewed and the relationship between the number of queries, the number of actual Web sites visited, and time between multiple site visits. The implications for Web search engines and services, Web sites and Web users are discussed.

Web search services are now a major source of information for a growing number of people. We need to know more about how users search Web search engines to improve the effectiveness of their information retrieval. This paper reports results from a major study exploring users ’ information searching behavior on the EXCITE Web search engine. The study is the first to investigate Web users ’ successive searching behavior as they conduct related searches over time on the same or evolving topic. A total of 316 EXCITE users responded to an interactive survey accessed through EXCITE’s homepage. Users provided information on their search topics, intended query terms, search frequency for information on their topic, and demographic data. Results show that when searching the Web: users tend to employ simple search strategies; and often conduct more than one search (successive searches) over time to find information related to a particular topic. Implications for the design of Web search services are discussed.

Topic management is the task of gathering, evaluating, organizing, and sharing a set of web sites for a specific topic. Current web tools do not provide adequate support for this task. We created the TopicShop system to address this need. TopicShop includes (1) a webcrawler that discovers relevant web sites and builds site profiles, and (2) user interfaces for exploring and organizing sites. We conducted an empirical study comparing user performance with TopicShop vs. Yahoo. TopicShop subjects found over 80% more high-quality sites (where quality was determined by independent expert judgements) while browsing only 81% as many sites and completing their task in 89% of the time. The site profile data that TopicShop provides -- in particular, the number of pages on a site and the number of other sites that link to it -- was the key to these results, as users exploited it to identify the most promising sites quickly and easily. KEYWORDS information access, information retrieval, informat...

In this paper we explore the problem of Caching of Search Engine Query Results in order to reduce the computing and I/O requirements needed to support the functionality of a search engine of the world-wide web. Based on traces from search engines we show that there is significant locality in the queries asked, that is, 20-30% of the queries have been previously submitted by the same or a different user. Using trace-driven simulation we show that medium-sized caches can hold most of the frequently-submitted queries. Finally, we propose and evaluate a new cache replacement algorithm named LRU-2S, that takes into account both the frequency and the recency of access to a page when making a replacement decision.

Agents that provide just-in-time access to relevant online material by observing user behavior in everyday applications have been the focus of much research, both in our lab, and elsewhere. These systems analyze information objects the user is manipulating in order to recommend additional information. Designers of such systems typically make the assumption that objects similar to the one being manipulated by the user will be useful to her. Our own experiments show that users do find many of the documents retrieved by a system of this type are relevant. Yet in the context of a specific task, users find fewer of these documents are useful. Our main point is that in order to make just-in-time information systems truly useful, we need to reexamine the "similarity assumption" inherent in many of these systems' designs. In light of this, we propose techniques that bring modest amounts of task-specific knowledge to bear in order to perform lexical transformations on the queri...

This paper provides an introduction to interactive information retrieval--the study of human interaction with information retrieval systems. Interactive information retrieval may be contrasted with the "system-centered" view of information retrieval in which changes to information retrieval system variables are manipulated in isolation from users in laboratory situations. The paper elucidates current models of interactive information retrieval, namely, the episodic model, the stratified model, the interactive feedback and search process model, and the global model of polyrepresentation. Future directions for research in the field are discussed. Keywords: interactive information retrieval; information retrieval; interactive models