What Characterizes the Usability of Web Applications?

11.3 What Characterizes the Usability of Web Applications?

Though the general explanations given above apply also to Web applications, it appears justified to emphasize usability specifics of Web applications. Usability is a quality characteristic with particular significance for Web applications and therefore media-specific design guidelines have to be taken into account in the design of usable Web applications (see section 11.4).

The greater significance of usability for Web applications versus traditional software products can be ascribed to the potentially global distribution of Web applications and to the special Internet philosophy. Manhartsberger and Musil (2002), pp. 16–20 summarize a few of these differences vividly:

• “Software is no longer sold in boxes”. There is no such thing as shiny and deceptive packaging in the Web. The term WYSIWYG gains a new significance: a Web site shows immediately what you get, and the Web-specific culture and user behavior exercises more pressure on the vendors (see further below).

• “You can’t train surfers”. It is customary to conduct training programs, especially for complex software products, to ensure their efficient, effective, and satisfactory use. Unfortunately, many training programs are used to compensate for product defects by trying to adapt users to product restrictions instead of taking the opposite way. Fortunately, this is generally impossible on the Web, so that particular emphasis has to be placed on making Web applications self-explanatory (see section 1.3.1).

• “Real products are (not) sold on Web sites”. Though many Web applications are designed for the purpose of selling products, a large number of studies disclosed that the percentage of online customers who actually effect purchases in the Web is relatively low (see Footnote 1). Despite their original buying intentions, many users get virtually lost on their way between entering an online store and checking out at the cashiers, while just about finding an emergency exit. What real-world store owner would be happy with this situation? In particular the dot-com crisis in e-commerce about the turn of the millennium has shown clearly that ignoring the needs of potential customers won’t go unpunished. A famous example was the online sports wear store ( Boo.com ); its downfall was essentially caused by violation of numerous usability principles.

• “On the Internet nobody knows you’re a dog”. In his cartoon 3 published in The New Yorker in 1993, Peter Steiner illustrated humorously the anonymity of Web users. The cartoon

3 The New Yorker (Vol.69 (LXIX), no.20) p.61, July 5, 1993; you may launch your favorite search engine, typing “Steiner New Yorker Internet Dog” to find this cartoon.

11.3 What Characterizes the Usability of Web Applications? 223 shows a dog explaining to another dog that you can surf the Web without being recognized.

Communication on the Web is unilateral, i.e., a Web application cannot react like a real salesperson and adapt quickly to a customer.

The last point in particular is a fundamental Web usability problem: user categorization. It is extremely difficult to make assumptions about the users an application may expect. While at least rough assumptions about users, devices, etc., can be made during the development of conventional applications, the Web is an uncharted territory for the developer. In addition to different factors that concern the users themselves, the technical side conditions of a Web application’s use are extremely heterogeneous.

For example, though the number of broadband connections increases constantly, there are still a number of users working exclusively with conventional modems. Apart from the network connec- tion, the available graphics card or operating system also play an important role. For these reasons, the fundamental guidelines established in usability research work almost a decade ago are still relevant, such as keeping the loading volume of at least the start page as low as possible, assuming

a small color depth, or avoiding restrictions to the specific software platforms (Nielsen 1999b). Paradoxically, recent developments in the field of the mobile Internet, GPRS, UMTS, etc.,

resurrect old minimum requirements, because small screens and tiny keyboards are experiencing

a revival. To cater to mobile devices, websites and services should offer much shorter articles, dramatically simplified navigation, and highly selective features, retaining only what’s needed in a mobile setting (Nielsen 2003).

In connection with issues about the usage environment, however, we don’t have to rely entirely on assumptions. For example, if it’s not a matter of establishing a new Web application, but of

a new version of a previously introduced application, then we can use information about past usage patterns in the development process, e.g., by analyzing log files (see Chapter 8). Though the importance of training Internet users has decreased, as mentioned earlier, it is still possible to profit from learning mechanisms. Interaction patterns that users have learned from well-known Web applications can be utilized in a new context. If a user recognizes elements or mechanisms on a Web site he or she knows from other Web sites, then this user will easily find his or her way around. This is a fact Web developers could benefit from. Unfortunately, it is not considered enough in Web engineering though generally known in other engineering disciplines. Would we accept having to take driving lessons again if we bought a different brand of car to be able to drive it? Hardly. But many Web sites demand just that. If you think of Web applications as virtual cars, you sometimes find the gas pedal at eye-level, the gear lever on the back seat, and the brake in the trunk. No wonder nobody wants or is able to drive (use) such a car (Web application).

The car metaphor also helps to refute the popular argument among designers that usability awareness is detrimental to creativity. Would anybody seriously argue that the designs of a Ferrari Testarossa, a Rolls Royce, and a VW Beetle don’t differ much only because you can drive them in the same way?

In addition to the learning experience, human information processing has a number of other characteristics that are important for the usability of software products in general and Web applications in particular. The consideration or negligence, respectively, of user characteristics can make a Web application succeed or fail. Due to a lack of training and the large number of competing alternatives (that can be easily reached through search engines), Web applications have to be particularly intuitive and clearly designed for their users. Though it would be an

224 Usability of Web Applications unrealistic venture to try to optimally support each individual user, there are certain basic criteria

which allow to offer acceptable solutions, which are better than the current state-of-the-art in practice. Krug (2005) summarizes the basic idea in the title of his book, Don’t Make Me Think. Web applications have to allow everybody to operate them without trouble, without much thinking, and at a tolerable level of cognitive stress (see section 1.3.1). The following aspects are important to this end:

• Perception: The positioning, grouping, and arranging of contents on a Web site have to correspond to the mechanisms of human perception. These mechanisms, which are identical in almost all people, work largely unconsciously and automatically. One of the most important mechanisms is how humans perceive shapes. Things are not perceived as separate entities, but in relation to other things.

For example, a flowery meadow consists of millions of individual elements. Nevertheless, it is perceived as an entity or shape at first sight. Looking more closely, humans perceive structures, nuances, and details, where there are individual differences: a woman who likes flowers will perceive other aspects than, say, her son-in-law who is supposed to mow the meadow.

Using this analogy in the Web context, a Web site is also first perceived as an entity. In the next step, however, it should open up a structure that is as clear as possible for the user, excluding any uncertainties. Of course, there can be differences, and they are meaningful. Somebody interested in applying for a job at a hotel will look at the information differently than somebody who wants to reserve a room. The application should support both.

• Memory: The capacities of human information processing are very limited. If we try to memorize a shopping list and, as we leave the house, meet a friend or neighbor who tells us his new phone number, then chances are that we will either forget something we wanted to buy or won’t remember that neighbor’s new phone number once we get back home.

Similar things happen to users when they surf the Web. In the course of interaction, we normally have to memorize a list of things to do (buy something, search for information, etc.), including data. This can be difficult due to unnecessary stress with a wealth of information in the form of animations, advertising banners, links, etc., so that we easily lose track of what we actually wanted to do.

• Attention: One of the most important mechanisms to compensate for the problems described above is attention. If the mental capacity is insufficient to process a lot of information simultaneously, then focused attention allows to concentrate on a specific aspect and fade out everything else. Now, humans are subject to different archaic automatisms, which can influence this willfully controlled focus. For example, look at how we react to moving objects. Our earliest ancestors had to watch out for wild animals, i.e., they had to react to minimal far-away movements to ensure they had sufficient time to escape. We still have these reflexes today. On the Web, our “enemies” are not tigers or bears, but advertising banners and popup windows. Though the understanding of Web technology steadily enhances, many Web site operators still think that a high degree of multimedia effects attracts users, without taking into account that they pull away capacities and attention from the actual task, impairing the effective use of a Web application.

The following section discusses exemplary design guidelines that consider these technical and user-specific restrictions.

11.4 Design Guidelines 225