The practice of sending copies of letters is not new, and electronic copy practices have clearly taken up certain elements from the use in traditional correspondence.
With the development of email as a central tool for workplace communication, the practice of sending copies has proliferated. The ease of adding recipients to the copy field has made the electronic version more pervasive and has led to new interactional practices.
Employees use copies to achieve routine collaboration in their daily work tasks, sharing knowledge, prompting feedback, and seeking support. This contributes to creating new patterns of interaction and to erasing traditional hierarchical structures and established lines of information flow.
Thus, the practice of copying others in can also serve to reinforce hierarchical structures within the organization. It makes it easier for participants to appeal to superordinates to back their claims in cases of conflict and thereby to stress the importance of institutional status rather than the force of the argument.
Copying in recipients gives employees the opportunity to build their professional identity by presenting their ideas and achievements to other members of the organization, and especially to superordinates.
But the indiscrimanadas copies can generate extra and unproductive work to the recipients. This happens frequently when the option "replay all" is used unnecessarily.
Digital literacy involves competence in participating in electronically-mediated social activities among multiple participants. It involves competence in using various addressing devices to differentiate among recipients with varying participation statuses.
Digital media literacy also involves receptive skills, such as interpreting the relevance of a message according to one's status as primary or secondary recipient. It includes the competence to fill in with relevant context, to sort messages with various degrees of relevance, and reply to them accordingly. Digital literacy involves a strategic competence, that is, a competence in using copies in order to achieve different goals.
If you want to read more about this subject see this study from Norwegian School of Management.