This lecture covered web accessibility and the WCAG initiative. It defined accessibility and discussed how a focus on presentation over content can negatively impact accessibility. The WCAG provides guidelines to make web content accessible, such as providing text alternatives for non-text content and ensuring users can navigate content in an intuitive order. Examples of accessibility issues included CAPTCHAs that are difficult for screen readers and drop-down menus that are not operable without a mouse. Testing tools like the web developer toolbar and Lynx browser were also introduced.