Abstract — Many websites remain inaccessible for people with disabilities, despite the availability of relevant guidelines and tools. This is mainly due to lack of training of Web designers on accessibility technology. This need is addressed, by ESALP, presented in this paper, a web-based application that is meant to be used as a tool to disseminate and teach Web accessibility guidelines and good design practices. The tool adopts an example-based learning approach. First, it exposes people to the accessibility impasses that arise when certain, established guidelines are violated, and then provides concise advice on how to avoid or resolve them. These examples were derived from an in-depth, Web accessibility evaluation study of 50 Greek websites. The results of this study, in agreement to similar studies, also indicated that the accessibility of the Greek Web is rather low. We argue that the presented tool could help in improving the accessibility of websites by increasing awareness, motivating and educating Web development stakeholders on the subject of accessibility. Index Terms — Human-computer interaction, Web accessibility, educational tool, example-based learning, accessibility study I. INTRODUCTION N today’s information society the Web has become an invaluable way to access information, exchange ideas and do business. The Web is used by a constantly growing number of people of different ages, cultures, education, and with different physical and cognitive abilities. It is therefore essential to ensure equal access to the Web and provide the same opportunities for all people [1]. As T. Berners-Lee, inventor of the Web, eloquently stated: “The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.” Web accessibility refers to the practice of making websites usable by people of all abilities and disabilities [2]. The following excerpt from [19] stresses the importance of ensuring accessibility of websites for people with disabilities. This is the author's version of the work. You can quote this paper as: “Katsanos C., Tsakoumis A., Avouris N. (in press). Web Accessibility: Design of an Educational System to Support Guidelines Learning. In Proceedings of the 13th Pan-Hellenic Conference on Informatics, PCI 2009 (pp.), Corfu, Greece, 10-12 September, 2009” “To me (a quadriplegic) the Internet occupies the most important part in my life. It is my feet that can take me to any part of the world; it is my hands which help me to accomplish my work; it is my best friend - it gives my life meaning. […] On the Internet, I am no longer a quadriplegic. […] I am again an orthopedic surgeon, conducting online clinical consultations […].” People with disabilities typically use assistive hardware and software technologies to access the Web. For instance, people with blindness may be accessing a webpage using a screen reader, such as JAWS, that transforms the content of the computer screen into synthesized speech. As a second example, people with motor disabilities may be using a non- traditional input or output device to access a website, such as a head-mouse or a Braille display. Nevertheless, assistive technologies are only helpful if the website is designed in a way that allows access through such technologies. Nielsen [3] argues that “making the Web more accessible for users with various disabilities is to a great extent a matter of using HTML the way it was intended: to encode meaning rather than appearance.” For instance, HTML heading tags are often used to serve presentation purposes instead of conveying document structure. This approach invalidates the headings-based navigation mechanism provided by typical screen readers. As a second example, using device-dependent event handlers, such as “onmouseover”, can render parts of a website’s content inaccessible to people that cannot use typical input devices. Key knowledge about developing accessible websites comes into the form of guidelines. The two most widely-known sets are Section 508, a USA law (www.section508.gov), and Web Content Accessibility Guidelines (WCAG − [16], [17]) published by W3C, the international organization for Web standards. Various countries, such as Canada, Philippines, Spain, Sweden and United Kingdom [2], have also produced national accessibility guidelines. Despite the abundance of available guidelines, studies show that at least 70% of websites continue to have low accessibility [4]–[8]. One of the main problems of guidelines is that they are often stated at such an abstract level that tends to make unclear how to operationalize them [9]. In addition, they come in a context-independent form that tends to make Web Accessibility: Design of an Educational System to Support Guidelines Learning Christos Katsanos, Athanasios Tsakoumis, and Nikolaos Avouris Human-Computer Interaction Group, Electrical and Computer Engineering Dept., University of Patras, GR-26500 Rio Patras, Greece I