Data governed by data retention rules may be referred to by different terms, e.g., “meta-”, “traffic” or “location” data. The term “data related to use of electronic communications services” encompasses all. It should be noticed that content data are out of scope of data retention rules.
Data retention rules concern data generated in the operation of certain services. These services are run by some and used by others. Both the services and the communications equipment involved, may vary. This makes for sorting the data into different categories, for instance according to criteria concerning:
The services (telephone, internet access, online communication services, networks);
The person offering the service/processing the data (provider, user, end-user, user-ID);
The person using the service (subscriber, registered user, user, end-user);
The communication per se (A-and B number, IP-address, time, duration);
The identity of the communications equipment used in the communication;
The geographical area where a specific communications device is or has been used, etc.
The categorization indicates that there is a great variety of data that could be retained, and that different layers in the chain of communications services (several layers of providers and users may be involved in one communication) could be relevant data retention points. The former is a question of the material scope of the rules, the latter of the personal scope of the rules. The technological complexity adds to the intricacies of EU law the legislator is faced with in this field. This could help explain the differences of the data retention rules of the Nordic countries, they seem to vary in every aspect of the categories set out above.