AdMob Mediation is a feature that lets you serve ads to your apps from multiple sources, including the AdMob Network, third-party ad networks, and AdMob campaigns. ... This guide is your one-stop shop for integrating mediation into your AdMob app.

Deprecated Google Cloud Messaging for Android (GCM) is a service that allows you to send data from your server to your users' Android-powered device, and also to receive messages from devices on the same connection. The GCM service handles all aspects of queueing of messages and delivery to the target Android application running on the target device. GCM is completely free no matter how big your messaging needs are, and there are no quotas.

Ad Manager uses the Google Mobile Ads SDK which helps app developers gain insights about their users and maximize ad revenue. To do so, the default integration of the Mobile Ads SDK collects information such as device information. iOS setup Android setup.