Rich media is a digital advertising term for an ad that incorporates advanced features such as video, sound, or other elements that encourage people to interact with the content.
In the case of text and display ads, the advertising message passes through words and images respectively. The rich media format allows you to interact with the ad in many ways: by unfolding it, by floating it, etc. Plus, you get aggregated statistics about your audience behavior (e.g., number of expands, multiple exits, and video complete plays) to get more accurate data on your campaign results.
The rich media format allows agencies to create complex ads that can elicit a strong response from the user. HTML5 technology offers the possibility of superimposing, on the same location, several levels of content, such as videos, games, tweets, etc. Do you just want to generate clicks, or do you have a bigger goal to promote your brand awareness? Rich media is exactly the format for you.