Advertisers, agencies, and brands are a part of the ecosystem around your ads. You can associate any campaign with all of these client types, which allows you to track a report on progress for these organisations. The Clients tab () gives you an overview of all campaigns for each advertiser, agency, and brand in your system.
Pulse also helps you to avoid having competing advertisers (direct and programmatic) or brands appearing in the same ad break. By defining and populating the Client categories you avoid these types of client clashes.