Current Projects: Web Naviagtion.

Co-researchers (email): Saul Greenberg, Bruce McKenzie, Michael Moyle, and Steve Jones

Improving Web Page Revisitation: Analysis, Design, and Evaluation

In this paper, we distill several years of our research on understanding and improving how people return to their previously visited web pages. Our motivation is that web page revisitation is one of the most frequent actions in computer use, and consequently any interface improvements in this area---no matter how small---can have a very large effect. We report our findings across five categories of revisitation research: characterisations of user behaviour; system models of navigation and their impact on the user s understanding; interface methods for increasing the efficiency of the Back button; alternative system models for navigation; and alternative methods for presenting web navigation histories. The behaviour characterisation shows that revisitation is a dominant activity, with an average of four out of five page visits being to previously seen pages. It also shows that the Back button is heavily used, but poorly understood. Three interface strategies for improving web page revisitation are described. The first, a gesture-based mechanism for issuing the frequent Back and Forward commands, addresses low-level interface issues, and is shown to be both popular and effective. The second, a 'temporal' behaviour for the Back and Forward buttons, aims to overcome the problems associated with poor understanding of the current behaviour of Back. Although the results do not conclusively show advantages for the temporal behaviour of Back, they strongly suggest that revisitation can be improved by providing temporally ordered lists of previously visited pages. The third interface scheme investigates how next-generation browsers could integrate the current tools for revisitation into a single utility, and how simple visualisation methods can be used to aid users in identifying target pages displayed in miniature.

Gesture Navigation: An Alternative `Back' for the Future

Web navigation relies heavily on the use of the `back' button to traverse pages. The traditional back button suffers from the distance and targeting issues that govern Fitts' Law. An alternative to the button approach is the use of marking menus---a gesture based technique shown to improve access times of commonly repeated tasks. This paper describes the implementation and evaluation of a gesture-based mechanism for issuing the back and forward commands in web navigation. Results show that subjects were able to navigate significantly faster when using gestures compared to the normal back button. Furthermore, the subjects were extremely enthusiastic about the technique, with many expressing their wish that "all browsers should support this". Subjective measures also showed significantly higher ratings for the gesture system over the back button. Finally, subjects found the `flick' gesture easy to learn.

Pushing Back: Evaluating a New Behaviour for the Back and Forward Buttons in Web Browsers

The Back button on web browsers is one of the world's most heavily used user interface components, yet its behaviour is commonly misunderstood. This paper describes the evaluation of a `temporal' alternative to the normal `stack-based' behaviour of Back and Forward. The main difference of the temporal scheme is that it maintains a complete list of previously visited pages. The evaluation compares the efficiency of the stack and temporal schemes in an `out of the box' scenario in which the subjects were asked to use a `new' version of a commercial browser without any explanation of the presence or absence of new features. This scenario allows us to predict the likely usability impact if commercial browsers were released supporting the temporal scheme. As expected, the results showed no reliable difference for many standard activities such as `hub-and-spoke' browsing. Also as expected, the temporal scheme was reliably slower for multi-level backtracking to parent pages. Interestingly, however, the temporal scheme polarized user performance in more complex navigation activities, with subjects either becoming very efficient or inefficient. Overall, the results are positive and indicate that the temporal scheme can be adapted to improve web navigation.

An Empirical Analysis of Web Use

This paper provides an empirical characterisation of user actions at the web browser. The study is based on an analysis of four months of logged client-side data that describes user actions with recent versions of Netscape Navigator. In particular, the logged data allows us to determine the title, URL and time of each page visit, how often they visited each page, how long they spent at each page, the growth and content of bookmark collections, as well as a variety of other aspects of user interaction with the web. The results update and extend prior empirical characterisations of web use. Among the results we show that web page revisitation is a much more prevalent activity than previously reported (approximately 81% of pages have been previously visited by the user), that most pages are visited for a surprisingly short period of time, that users maintain large (and possibly overwhelming) bookmark collections, and that there is a marked lack of commonality in the pages visited by different users. These results have implications for a wide range of web-based tools including the interface features provided by web-browsers, the design of caching proxy servers, and the design of efficient web-sites.

WebView: A Graphical Aid for Revisiting Web Pages

Current commercial web browsers such as Netscape Navigator and Microsoft Internet Explorer provide a wide and diverse range of utilities, such as history lists and bookmarks, that support revisiting previously seen pages on the web. Yet previous research indicates that these utilities are largely unused. In this paper, we present an alternative utility called WebView; a prototype designed to improve the efficiency and usability of page revisitation. It does this by paying particular attention to how previous pages are represented visually, and by integrating many revisitation capabilities into a single display space. Our preliminary evaluation of WebView indicates that users are enthusiastic about the functionality provided, and that it improves the efficiency of some navigational acts.

The WebView Interface

Getting Back to Back: Alternate Behaviors for a Web Browser's Back Button

This paper concerns the ubiquitous Back button found in most Web browsers. First, we outline why Back is an effective method for revisiting WWW pages: a) It allows rapid return to very recently visited pages, which comprises the majority of pages a person wishes to return to; b) People can use it even with a na´ve model of the way it works; c) People usually keep it on permanent display because it is visually compact; and d) Back works via a simple 'click until the desired page is recognized' strategy. Second, we investigate the behavior of Back. The typical stack-based behavior underlying Back is problematic because some previously seen pages are not reachable through it. To get around this problem, we offer several alternate behaviors of the Back button, all based upon a recency model. The advantage of recency is that all previously seen pages are now available via Back. Because trade-offs exist, we present both problems and prospects of these different Back behaviors in various navigational situations.

Which Way Now? Analysing and Easing Inadequacies in WWW Navigation

This paper examines the usability of the hypertext navigation facilities provided by World Wide Web client applications. A notation is defined to represent the user's navigational acts and the resultant system states. The notation is used to report potential, or `theoretical,' problems in the models of navigation supported by three web client applications. A usability study confirms that these problems emerge in actual use, and demonstrates that incorrect user models of the clients' facilities are common. A usability analysis identifies inadequacies in the clients' interfaces.

Motivated by the analysis of usability problems, we propose extensions to the design of WWW client applications. These proposals are demonstrated by our system WebNet which uses dynamic graphical overview diagrams to extend the navigational facilities of conventional World Wide Web client applications. Related work on graphical overview diagrams for web navigation is reviewed.

A review of novel systems for visualising web navigation

Co-researcher (email): Steve Jones

The World Wide Web (WWW) is a successful hypermedia information space used by millions of people, yet it suffers from many deficiences and problems in support for navigation around its vast information space. In this paper (300K pdf) we identify the origins of these navigation problems, namely WWW page description languages, WWW page design and WWW browser design. Regardless of their origins, these problems are eventually represented to the user at the browser's user interface. We therefore investigate improvements to browser interfaces that promise to assist navigation. We identify key issues in the adoption of such a strategy. These include visualisation of WWW subspaces, visualisation techniques, visualisation generation, browser independence and navigation support functions. We consider and classify existing systems and related work with respect to these issues. The identification of these issues and the discussion of exemplar systems will help to guide future design of WWW navigation tools.

Associated work at Calgary

A paper summarising Linda Tauscher's quantitative work on page revisitation in WWW.
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