The latest version of Google Play Services adds three new components, Google Analytics API, Tag Manager, and the Address API, and adds features to the core Google Play Game services API and to the Drive API.

Both the Analytics API and Google Tag Manager have existed as standalone technologies for Android for some time, but Google is now incorporating them into Google Play services.

Google Analytics allows you to get detailed statistics on how you app is being used by your users, for example what functionality of your app is being used the most, or which activity triggers users to convert from an advertised version of an app to paid one.

Tag Manager lets you change characteristics of your app on-the-fly, for example colors, without having to push an update from Google Play.

The Address API is new and allows developers to request access to addresses, for example to fill out a delivery address form. This is seen as a convenience for the user - a user interface component is presented where they select the desired address with the result that the form is filled for them. This API cater for cases where the Location data, which developers have used up to now, is either not accurate or the user actually wants to use a different address than their current physical location.

The new feature in the Google Play Game services API is  game gifts, which allows players to send virtual in-game requests to anyone in their Google+ circles or through player search. Using this feature, the player can send a 'wish' request to ask another player for an in-game item or benefit, or a 'gift' request to grant an item or benefit to another player.

The Android Developers Blog announcement states:

This is a great way for a game to be more engaging by increasing cross player collaboration and social connections. We are therefore glad to add this functionality as an inherent part of the Games API, it is an much-wanted extension to the multi-player functionality included a couple of releases ago.

Several features are added in this release to the Google Drive for Android API, recently added as a member of the Google Play services API family.

• Pinning - Files that should be kept up to date locally can now be pinned, ensuring availability when the user is offline. This is great for users that need to use your app with limited or no connectivity
  
  
• App Folders - An app often needs to create files which are not visible to the user, for example to store temporary files in a photo editor. This can now be done using App Folders, a feature analogous to Application Data Folders in the Google Drive API
  
  
• Change Notifications - You can now register a callback to receive notifications when a file or folder is changed. This mean you no longer need to query Drive continuously to check if the data has changed, just put a change notification on it

The ability to access a number of new metadata fields has also been added.