For more examples of web advertising, check out the Animation section
Also to note: For improving future web design/development and user interface design I am currently studying the concepts and principles of Web 2.0 (¹) and User-centered Design (²). I believe the concept of simplicity in Web 2.0 plays a role in how to create more reactive online advertisements.
¹Web 2.0 - A term often applied to a perceived ongoing transition of the World Wide Web from a collection of websites to a full-fledged computing platform serving web applications to end users. It refers to a supposed second-generation of Internet-based services—such as social networking sites, wikis, communication tools, and folksonomies—that emphasize online collaboration and sharing among users.
Source: 2020 Systems "Online Marketing Made Easy" Internet Glossary of Terms
²User-Centered Design (UCD) is a user interface design process that focuses on usability goals, user characteristics, environment, tasks, and workflow in the design of an interface. UCD follows a series of well-defined methods and techniques for analysis, design, and evaluation of mainstream hardware, software, and web interfaces. The UCD process is an iterative process, where design and evaluation steps are built in from the first stage of projects, through implementation."
Source: Shawn Lawton Henry and Mary Martinson, Accessibility in User-Centered Design