Audience targeting

This is a feature only available in Google Ad Manager 360. Audience solutions allow advertisers or buyers of your placements to reach the audience they want

In order to build a high-quality website/app, publishers need to care about the advertising content that will be displayed on their page. The main goal is to bring advertising content to the necessary users. It's also a part that advertisers are now asking for. Not only will it make your site more efficient, but it will also help increase your ad revenue.

In Content Ads - Best Practice

300×250px — Medium Rectangle
728×90px — Leaderboard
320×50px — Mobile banner

These 3 sizes are very popular in programmatic due to high demand by advertisers and because they yield higher CPM.