The new guidelines on targeting of social media analyses the various actors which are involved in targeting, which are divided to four categories: social media providers, social media users, targeters and other actors, such as data brokers and ad exchanges, which may be involved in the targeting process.

The main purpose of the guidelines is to clarify the roles and responsibilities of the social media providers and the targeters. In many cases both parties would be defined as joint controllers. The importance of correctly identifying these roles and responsibilities has been emphasized in judgements of the European Union's Court of Justice.

Three different mechanisms of targeting are addressed by the guidelines. The first is targeting on the basis of data provided by the user. The second mechanism is targeting based on the basis of observed data, which includes data that is provided by the user through the use of a service or device, or data that is collected by third parties. This category includes the use of technical measures such as pixels. The third mechanism is targeting based on inferred data. Profiling is typically involved in this mechanism, and assessment of automated decision making must be conducted to define whether it leads to legal or similarly significant effects.