IT departments typically have taken the lead in introducing email into organisations. Their focus is on the technology, so when they train staff in its use, they cover how to send an email, how to copy, forward, edit, attach a document and so on.
HR departments have their focus on people.
They cover training issues such as how to work with less stress, how to communicate, how to get your message across and how to manage your time. In short, staff have been trained in the technology, but not the human aspect of email. This, combined with the very nature of the medium, generates its own problems. There is a tacit assumption that email is like paper, and therefore the reading and writing skills people already have will suffice. This assumption is wrong.