The Gmail Objective-C SDK written by Google provides access to the JSON API considering Apple application development. It is compatible with iOS 3+ and Mac OS X 10.5+. Along with the access to the Gmail API, the Objective-C library can also interact with the AdSense, Blogger, Calendar, Drive, and Fitness Google APIs.
Do you remember a time when keeping track of your social networks meant only checking your inbox? Neither do I, but Microsoft is working on a solution that will eventually allow Outlook to integrate with a number of social networks like LinkedIn, Facebook and MySpace with the Outlook Social Connector.