This SDK is for C#/.NET developers interested in working with LinkedIn's social networking API. The SDK can be installed via NuGet and is currently in version 1.0.6. See the documentation for instructions and code examples for getting started. Note that the authors indicate that LinkedIn is modifying its developer program which may affect use of this package. See the SDK homepage for more information.
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.