Google this week introduced a new ad format in AdMob called App open ad format. App open ad format gives developers a way to monetize previously untouched inventory as users wait for an app to load.
According to Google, this new format enables ads to appear on the loading or splash screen as the user waits to open and use the app.
Google says that since the user is already waiting for the app to load, this format integrates seamlessly with the user experience.