The ACDL introduces a standard method to collect and store data about a visitors experience on a webpage and then make it easy to access this data. The goal of the ACDL is to reduce the effort to instrument websites by providing a standardized method to expose and access any kind of data for any script. The ACDL is platform agnostic, but is fully integrated into the Core Components for use with AEM.
If required, you can customize the ACDL with content from custom AEM Components by Inject component data into the data layer by extending a Sling Model and component HTL. Also Core Component data layer can be utilized to reduce effort. Core Component data attributes can be hooked into existing data layer events.
Here is a link to PDF which talks in-detail about the ACDL. Please have a look.