ability of Web applications to support web-related tasks with effectiveness, efficiency and satisfaction. Effectiveness represents accuracy and completeness when users achieve a specified goal. Efficiency is resource cost in relation to the accuracy and completeness. Satisfaction is the comfort and acceptability of use. ADA Compliance and Web Usability Web sites and application should be made usable for all users. ADA compliance play a major part in making web usability a seamless and satisfying experience. See Americans with Disabilities Act of 1990. Mobile Usability With so many different mobile devices (screen size, make,..), it is crucial to consider how the users accomplish their task on a small screen. Web usability components should be met for the mobile device. The users should be awarded with the same feeling of satisfaction and accomplishment as if they had used a desktop or laptop. - See also "Mobile Usability" by Jacob Nielsen Not only is the screen different, nowadays mobile users want different things than desktop users. According to a survey conducted by Google, users want mobile friendly websites as they use them every day for different tasks, i.e. research. Moreover, if a web site is mobile friendly, the users are more likely to return to it but are quick to leave if it is not. In summary, they want a website that is fast and simple to use - quick to load, has big buttons and readable text, and offer a way of engagement (videos, apps, social media, and other ways to contact the company). The three most sough-after things while browsing mobile are locations, opening hours and contact information. Make sure to include them. Check mobile-friendliness of a web site here. Usability for Multilingual Websites Multilingual websites should offer the same experience to the users, regardless of the website being in english, German, or Japanese. Websites should render the same way in all languages and all devices. UI Alterations because the language and characters used should still provide the different components of usability. Web Usability Criteria Nielsen's 10 heuristics Jakob Nielsen's heuristics are widely adopted in Interface Design. It provides expert reviewers with a set of principles to discover usability problems and then categorize and rate them in a quick way. This set of heuristics includes Visibility of system status, Match between system and the real world and so on. According to Jakob Nielsen, there are 10 general principles: Visibility of system status: