What are interstitial pages often used for?

Interstitial pages are typically used to display content that requires user interaction before they can access other content on a website. This often includes advertisements that promote a product or service, or age verification prompts that ensure users meet certain legal age requirements before proceeding. The nature of interstitials is to overlay or momentarily interrupt the primary content, which serves the purpose of drawing attention to critical information that needs user acknowledgment or action.

The other options represent different functionalities that are not inherently tied to the purpose of interstitial pages. For instance, user forums and direct content provision are normally found on dedicated pages or sections of websites rather than as temporary overlays. Similarly, search engine landing pages are specifically designed to fulfill search queries rather than interrupt content with ads or age confirmations. Therefore, the primary use of interstitial pages aligns with displaying advertisements or confirming user age, making this choice the most appropriate.