Full text available at: http://dx.doi.org/10.1561/1100000011 Web History Tools and Revisitation Support: A Survey of Existing Approaches and Directions Full text available at: http://dx.doi.org/10.1561/1100000011 Web History Tools and Revisitation Support: A Survey of Existing Approaches and Directions Matthias Mayer University of Hamburg Hamburg, Germany [email protected] Boston { Delft Full text available at: http://dx.doi.org/10.1561/1100000011 Foundations and Trends R in Human{Computer Interaction Published, sold and distributed by: now Publishers Inc. PO Box 1024 Hanover, MA 02339 USA Tel. +1-781-985-4510 www.nowpublishers.com [email protected] Outside North America: now Publishers Inc. PO Box 179 2600 AD Delft The Netherlands Tel. +31-6-51115274 The preferred citation for this publication is M. Mayer, Web History Tools and Revisitation Support: A Survey of Existing Approaches and Directions, Foundations and Trends R in Human{Computer Interaction, vol 2, no 3, pp 173{278, 2008 ISBN: 978-1-60198-226-1 c 2009 M. Mayer All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, photocopying, recording or otherwise, without prior written permission of the publishers. Photocopying. In the USA: This journal is registered at the Copyright Clearance Cen- ter, Inc., 222 Rosewood Drive, Danvers, MA 01923. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by now Publishers Inc for users registered with the Copyright Clearance Center (CCC). The `services' for users can be found on the internet at: www.copyright.com For those organizations that have been granted a photocopy license, a separate system of payment has been arranged. Authorization does not extend to other kinds of copy- ing, such as that for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale. In the rest of the world: Permission to pho- tocopy must be obtained from the copyright owner. Please apply to now Publishers Inc., PO Box 1024, Hanover, MA 02339, USA; Tel. +1-781-871-0245; www.nowpublishers.com; [email protected] now Publishers Inc. has an exclusive license to publish this material worldwide. Permission to use this content must be obtained from the copyright license holder. Please apply to now Publishers, PO Box 179, 2600 AD Delft, The Netherlands, www.nowpublishers.com; e-mail: [email protected] Full text available at: http://dx.doi.org/10.1561/1100000011 Foundations and Trends R in Human{Computer Interaction Volume 2 Issue 3, 2008 Editorial Board Editor-in-Chief: Ben Bederson Human{Computer Interaction Lab University of Maryland 3171 A. V. Williams Bldg 20742, College Park, MD Editors Gregory Abowd (Georgia Institute of Technology) Jonathan Grudin (Microsoft Research) Clayton Lewis (University of Colorado) Jakob Nielsen (Nielsen Norman Group) Don Norman (Nielsen Norman Group and Northwestern University) Dan Olsen (Brigham Young University) Gary Olson (UC Irvine) Sharon Oviatt (Oregon Health and Science University) Full text available at: http://dx.doi.org/10.1561/1100000011 Editorial Scope Foundations and Trends R in Human{Computer Interaction will publish survey and tutorial articles in the following topics: • History of the research Community • Online communities • Design and Evaluation • Games • Ergonomics/Human Factors • Communication technologies • Cognitive engineering and • Interdisciplinary influence performance models • The role of the social sciences in HCI • Predictive models of interaction • MIS and HCI • User-centered design processes • Graphic design • Participatory design • Artificial intelligence and the user • Graphic design interface • Discount evaluation techniques • Architecture and the role of the • Design and interaction physical environment • Ethnography • Advanced topics and tends • Theory • Information visualization • Models of cognition • Web design • Empirical methods of evaluation • Assistive technologies • Qualitative methods of design • Multimodal interaction and evaluation • Perception and the user interface • Technology • Specific user groups (children, elders, • Programming the graphical user etc.) interface • Sensor-based or tangible interaction • Input technologies • Ubiquitous computing • Output technologies • Virtual reality • Computer supported cooperative • Augmented reality work • Wearable computing • History of CSCW in HCI • Design and fashion • Organizational issues • Privacy and social implications Information for Librarians Foundations and Trends R in Human{Computer Interaction, 2008, Volume 2, 4 issues. ISSN paper version 1551-3955. ISSN online version 1551-3963. Also avail- able as a combined paper and online subscription. Full text available at: http://dx.doi.org/10.1561/1100000011 Foundations and Trends R in Human{Computer Interaction Vol. 2, No. 3 (2008) 173{278 c 2009 M. Mayer DOI: 10.1561/1100000011 Web History Tools and Revisitation Support: A Survey of Existing Approaches and Directions Matthias Mayer Department of Informatics, University of Hamburg, Hamburg, Germany, [email protected] Abstract Millions of web pages are visited, and revisited every day. On aver- age, every second page loaded was already visited before by the same user | individual means for recurrence rates range between 20% and 72% (cf. p. 24). People revisit pages within a session or between paral- lel ones, they reuse web-based tools habitually, monitor specific content or resume interrupted sessions, and they want to re-find content after longer periods of time. Current history tools that support such revisits show unique and severe shortcomings. Often, revisits are cumbersome, more than necessary. This survey summarizes existing knowledge about revisitations on the web, and surveys the potential of graphic-based web history tools. A taxonomy of revisit-types distinguishes between short-, medium-, and long-term revisits, but also intra- and inter-session revisits. Assisted by a clear nomenclature this provides more clarity to the current discus- sion. The potential use of graphic-based tools is analyzed and discussed with respect to the found categories. The value of the current, mainly Full text available at: http://dx.doi.org/10.1561/1100000011 non-graphical history tools, such as back button, bookmarks, history list, search engines, and search bars is examined and related to the potential offered by graphic-based tools. The survey provides summaries of key studies and bodies of research for those who are interested in improving the web users' experience by simplifying the processes of going back to resources visited seconds, minutes, hours, weeks, or even months ago. It is meant for developers and researchers, browser and search engine producers, web usability professionals, and those who feel an irresistible urge to creatively inno- vate the web. The time has come to design and offer more appropriate history support. This survey aims at providing a foundation, as well as valuable ideas for doing so. Full text available at: http://dx.doi.org/10.1561/1100000011 Contents 1 Introduction 1 1.1 Overview Over the Sections 3 2 Web-Usage and Revisitation Types 5 2.1 Responsibility for the Information Medium No. 1 5 2.2 Revisitation: Definitions and Types 7 2.3 Revisitations Based on Hypertextual Structure 14 2.4 Revisitations Based on Task Structure 16 2.5 Summary of Revisitation Behavior Analysis 20 3 Contemporary History Support 33 3.1 History Support in Current Web Browsers 33 3.2 Major Shortcomings of Current History Support 44 3.3 Approaches to Overcome Current Shortcomings 47 4 The Future of Visual Web Histories 75 4.1 Design Implications for Visual Web Histories 75 4.2 Extending the Vision of the Web's Future 79 5 Conclusions 83 Acknowledgments 87 References 89 ix Full text available at: http://dx.doi.org/10.1561/1100000011 1 Introduction Presumably man's spirit should be elevated if he can bet- ter review his shady past and analyze more completely and objectively his present problems. He has built a civi- lization so complex that he needs to mechanize his record more fully if he is to push his experiment to its logical conclusion and not merely become bogged down part way there by overtaxing his limited memory. Vannevar Bush, 1945 [52, p. 46] To accomplish our targets, to reach our goals, and also to manage the small things in day-to-day life, we spend a great amount of our time looking back, establishing back references, and remembering. To build the new, we seize the existing. To do research, we re-search the known. To progress technology, we examine the past. This is a basic human principle. In order to free our memory, we use external aids. We do not remem- ber all that we read. Instead, we re-consult a book. To make such 1 Full text available at: http://dx.doi.org/10.1561/1100000011 2 Introduction back references successfully, we must be able to rely on the used aids and tools. This applies for books just as well for e-mails, and web pages. When using the web, people often revisit earlier visited web pages. Such revisits appear in almost every web-based activity [256]. They vary in character and motivation | they appear in the short- and long-term, they refer to single or multiple pages, they are motivated by reviewing same or modified content. In our study, [213] showed that web users switch back and forth between parallel sessions, resume suspended sessions, re-utilize or monitor specific information, and try to re-find information found long ago. This results in short-, medium-, or long- term revisitations.1 What all these behaviors have in common is that one or more web pages are being revisited. A big variety of history tools and tech- niques like the back-button, browser tabs, bookmarks, and personal- izable search engines already support such revisits. However, most of these techniques still show substantial shortcomings and several impor- tant situations both of short- and long-term revisitation lack adequate support, thereby absorbing an unnecessary amount of time and cog- nitive capacities.