It is apparent that the internet-based and computer-mediated tools can be considered as the most recent step in the development of communication technologies. This paper aims at investigating the type of impact computer-mediated communication (CMC) tools' use has on Moroccan EFL university students' writing skills and performance. Two research instruments were used to collect the needed data, a questionnaire and a writing task. The findings reveal that the use of CMC tools has a positive impact on students' writing skills and performance. Yet, the results obtained from the writing task show that the use of CMC tools has a detrimental impact on students' academic written productions because most students failed to confine to the standards of academic writing in terms of layout, organization, style, level of formality, grammar, content, mechanics and tone.