Simple LinkedIn PHP is a library for interacting with the LinkedIn API. The library was designed and tested for PHP 5.2+ and is not expected to work with PHP 4. The only prerequisite for Simple LinkedIn PHP is the PHP cURL library.
Google has long fielded complaints of sign-in requirements associated with Google Play Games. The Google+ requirement and multiple sign-ins required for multiple games has been a hotbed of frustration. Google announced the end of both requirements as part of a Google Play Games API model change.
Facebook has rewarded a 10 year-old boy from Finland with a $10,000 bounty for discovering an authentication-related vulnerability in the Instagram API that could have enabled a hacker to delete comments of any user on the popular social photo sharing service even without an Instagram account.