The data layer is a library of data that describes an action’s context. It contains a variety of information, including technical (e.g. device used, access protocol), contextual (e.g. type of action, section, banner content), marketing (e.g. origin, purchase, participation or not in a game), legal (e.g. tracking optout) and CRM (e.g. user segment, login username if applicable) data.
The information contained in a data layer can be public or private, encrypted or unencrypted. The elements within come in various forms (text, amount, number, etc.) and can be hierarchised. Vendors don’t need all the information contained in a data layer; the data is filtered by a TMS, before being transformed and transferred to the solutions that use it.
The data layer’s nature is often representative of the marketing maturity of the digital team. Generally, data layers exist to meet the needs and expectations of both the marketing team and the technology partners. If a solution needs a variable to create its value, it must collect it. Thus, first-generation data layers were essentially centred around qualifying content. The second generation incorporate more variables that allow for visitor profiling (customer status, segment, scoring, etc.). The third generation will perhaps be invisible, at least partially, to facilitate Server-Side adoption.