Introduction

Mobile devices are getting better every day. Over the past few years, the world has seen an explosion of new devices like cellular phones, Palm Pilot, Pocket PC, and Auto PC. Mobile applications can now be developed to deliver different types of information to users around the world. Different mobile devices support different programming languages, such as WAP, WML, HTML, and Java. WAP is a global specification that allows mobile users to access information and services instantly through wireless devices (http://www.wapforum.org). The NTT equivalent to the WAP protocol is i-mode . NTT DoCoMo first introduced i-mode in Japan in February 1999, and as of today, it has more than 15 million users (http://www.nttdocomo.com). Unlike i-mode, which is available only from NTT DoCoMO in Japan, WAP is offered by many competing organizations throughout the world.

A major difference between the WAP and i-mode is that WAP runs WAP protocol, while i-mode runs on HTTP protocol. Development in WAP encompasses languages such as WML and WMLScript. In i-mode, the markup language used is cHTML (compact HTML). cHTML requires a cHTML gateway before a site can be accessed by users from their i-mode-compatible mobile phones. Similar to WAP, the underlying network technology does not matter. As such, the underlying network technology can be shared with Internet Web sites. Another application development language differentiate between WAP and i-mode is that while WAP uses cards to display WAP pages, i-mode does not facilitate the use of cards. This difference in concept is due to the different standards that have been adopted by WAP and i-mode. While the use of WMLScript can be difficult in the sense that missing or incorrect tags could crash the whole application, the use of cHTML is friendlier. The i-mode is able to display rich GIF and JPEG images, tables, multiple font types and font sizes, background colors, and style sheets on its browser. This is unlike WAP, which only displays WBMP images to WAP browsers.

WAP is a joint standardization effort for converging Internet and value-added services (VAS) to wireless devices like mobile telephones, pagers, and personal digital assistants (PDAs). Examples of VAS implementation include Short Message Services (SMS), mobile fax and data communication, auto roaming, e-mail updates, voicemail, and mobile Internet. This standardization effort is carried out by the WAP Forum, founded in June 1997 by a group of companies, namely, Ericsson, Motorola, Nokia, and Phone.com (formerly known as Unwired Planet). WAP is a universal open standard accepted by standardized bodies like the Telecommunications Industry Association (TIA) and World Wide Web Consortium (W3C).

WAP started as a result of the increasing demand for messaging and data services known as SMS, supported by the Global System for Mobile communications (GSM). After this, High-Speed Circuit-Switched Data (HSCSD) supported high-speed services for business users in 1999. HSCSD enables the transmission of data over a GSM link at speeds up to 57.6 kbit/s. By using HSCSD, a permanent connection is established between the caller and the calling parties for the exchange of data. Because it is circuit switched, HSCSD is more suited to applications such as videoconferencing and multimedia than "bursty"-type applications such as e-mail, which is more suited to packet-switched data (Furuskar, Naslund, & Olofsson, 1999).

WAP is developing rapidly due to support and demand from end-users who feel that using mobile devices is more personal than using a PC. This is because mobile devices like wireless phones and pocket devices are on all of the time (Compton, 2000). Furthermore, users of these devices can gain access to Internet services anytime and anywhere. People who require these types of services are "on-the-go" most of the time (consultants, managers, and staff who need to travel more often). Due to the development of mobile communications technologies in the 1990s, more people are able to and can afford to use mobile devices. These mobile devices, like cellular phones, are initially used for data communications, as in speech. Now, these mobile devices are not only portable, but they are also becoming the tools that people use to communicate and exchange information as well as gain access to services remotely, anywhere and at any time.

One of the common uses of remote services is electronic commerce (e-commerce). But, conducting e-commerce transactions over mobile devices has its limitations. Issues like limited memory, processing power, lack of standards, small keyboards, and small screens affect the amount and types of data that can be used in e-commerce transactions. Currently, most e-commerce applications available for mobile devices are limited to short transactions in the form of messaging transactions. In this chapter, we investigate the usability of mobile devices in e-commerce. As Singapore is considered one of the highest users of mobile devices in the world, this study explores users' concerns and acceptance of mobile devices. It also compares the use of mobile devices, such as cellular phones, PDAs, and laptops, to the fixed network using desktop computers. Issues covered in the study include sound effect, multimedia effect, user-friendliness of the user interface, navigation, speed of access to usage, users' preferences, convenience of usage, security of usage, and size of screen.