• Data reference period
• Geographic localization (Portugal)
• Economic activity (Section - CAE Rev. 3)

• REFERENCE PERIOD:  The length of time for which data are collected, e.g. a specific day, month or year.
• Electronic mail:  System that allows the sending of messages by computer inserted in communications networks or other communications equipment. E-mail is a computerized version of the services of internal correspondence or postal services. The messages may include voice, graphics, images and other information.
• ENTERPRISE:  Legal entity (natural or legal person) that is an organisational unit producing goods or services, which benefits from a certain degree of autonomy in decision-making, especially for the allocation of its current resources. An enterprise carries out one or more activities at one or more locations.
• ECONOMIC ACTIVITY:  Combination of resources such as labour, raw materials, equipment, etc., are joined, leading to the creation of specific goods or services. Regardless of the factors of production integrating the good or service produced, all activities generically imply an input of products (goods or services), a production process and an output of products (goods or services).

[Enterprises with 10 and more persons employed using e-mail/ Enterprises with 10 and more persons employed (NACE Rev. 2 C, D and E, F, G, H, I, J, K, L, M, N, S)]*100