What is an SDK?
SDK stands for Software Development Kit, which is a set of software tools or code snippets that allow you to include certain functionality into your own coding projects.
Why Do I Care?
By giving smartphone app developers an SDK, they can now include custom variables to track how the app is used. For example, if you have multiple versions of your app, you can capture which version the users was interacting with. You can determine if it was the paid version and capture exact version number and operating system version, too.
Just like Google Analytics on your Web pages, you can also track how people use the app, itself. For example, did they use a menu or do your users choose a long-press to perform the same task. You can even tell how they hold the device - portrait or landscape.
If your organization has a mobile app to complement your Web site, these SDKs are must-haves. Remember, mobile should not be looked at with a "because we have to" attitude. Mobile is its own category of interaction. The SDKs allow you to use your Google Analytics account to capture user data, make adjustments and repeat, the same as you would with Web visitors.