I believe that in the US we generally credit students with more computer literacy than they actually possess. There are several reasons for this, one being that technology has advanced and changed so rapidly that we have not had time for standard behaviors such as manners to develop. Hence students may not know how to interact appropriately via email, social media, chats, etc.
Additionally, students using the computer tend to spend a lot of time on only a few activities. They may not know how to really work word and data processing programs. Students arriving at college often find that the college expects them to use the computer as a productivity tool, but since so much of their past experience has been in using it as a social or entertainment interface, they are technically computer illiterate, at least in the way that the college expects them to use the equipment.