What kind of content does an iFrame primarily display?

An iFrame primarily displays third-party ads served from external ad servers because it acts as a container that allows a webpage to embed content from another source without compromising the webpage's integrity. This mechanism is crucial in digital advertising as it enables the serving of advertisements that are not hosted on the main server of the website being visited, ensuring that advertisers can deliver ads and track their performance independently.

By using iFrames, publishers can seamlessly integrate advertisements into their websites while keeping the ad content isolated from their own code. This isolation is beneficial for maintaining security and performance, as well as allowing for dynamic ad serving based on user data and preferences without impacting the main page’s load time.

While video ads and inline images are common types of content displayed on websites, they are typically embedded in a different manner and often do not utilize the iFrame structure to the same extent as third-party ads. Secure payments and transaction details might be implemented via iFrames for security reasons, but they are not primarily the focus of what iFrames are designed for in the context of ad serving.