Now that Google Mobile Ads is supported in Google Play services. The standalone AdMob SDK will be deprecated on 1 August, 2014. Play services supports Advertising ID, and provides seamless updates to Android users.
On 1 August, the Play Store will stop accepting new or updated apps that use the standalone Google AdMob SDK. The standalone SDK does not use the Advertising ID, and will therefore be affected by the Google Play Ad Policy. Google Play services still supports devices that don't have the Google Play store installed on it. The only difference is that devices without the Play Store will not receive automatic updates.
read more: Google Ads Developer Blog - Announcing Deprecation of the Standalone Android Google AdMob SDK
Related: Upgrade to the latest Google Mobile Ads SDK