These key concepts will help us to understand how Ad Manager is organized and how people use it.

•  Inventory is an advertising space we have available to sell. In Ad Manager, inventory takes in the form of ad units, which may be grouped into placements.
• Google Publisher Tags are short snippets of code placed on our pages to call ads from Ad Manager. These tags connect to the ad units we create in Ad Manager with our actual inventory.
•   Trafficking are the process of setting up and managing ad campaigns. In Ad Manager, we create orders, line items, and creatives, and we target them. We can target them to specific inventory and use other kinds of targeting as well, like showing our ads only in certain locations.
• Forecasting is the process of checking to see how much available inventory we will have in the future. Unlike, say, retail inventory, which we can simply count, it's hard to know exactly how many viewers we will have in the future — and even harder when we take different targeting scenarios into consideration. Ad Manager forecasting is designed to help us to sell all of our inventory while avoiding overselling.
• Reporting is where we go to check on active campaigns to see how they're delivering, and also to get information about completed campaigns. Ad Manager Reports is highly customizable, enabling us to discover insights about our inventory that can help us to create and sell more effective ad campaigns.
•  Account administration, shortened to "admin," is the set of tasks and tools which are used to administer our network: everything from setting up new users to enabling new features. Admin tasks is not everyday tasks, but they're important.
•  Traditional Ad Serving is the shared services provided to the publishers for the delivery of Ads from Google’s web servers to Target Properties based on criteria selected by the publishers and the advertisers and agencies advertising on the Target Properties.