Ad server: It houses different Ads from different Ad networks.
GAM: Only serving ads if there are ad units implemented on the order/line item.
GAM - Manager ad networks, compete for ad stack (Admanager cannot serve ads)
Need to add Ad Network (AdX) to GAM to server Ads.
Adx (AdExchange) advertising platform run by google
more complex set up needs GAM.
As an overview, the key steps are:
1. Count your ads per page
2. Evaluate your Page RPM #RPM
3. Look at your impression discrepancy
4. Monitor your revenue trend
5. Evaluate your fill rate
