Technology has provided increasingly popular ways for teenagers to communicate. However, there are worries that this trend is having a detrimental effect on their writing skills. In fact, many argue that writing quality has deteriorated due to the stunted writing style of social media, which plays havoc with spelling and grammar and weakens the ability to write more formal texts. In this perspective, we tested an innovative, student-centered learning program that combines technology, writing, collaboration, and feedback. The aim was to explore the extent to which a teacher’s feedback (metacognitive prompts) during collaborative writing tasks acts on students’ overall writing quality, use of metacognitive strategies, feelings of competence, and motivation to complete writing tasks. The participants were 22 high school students. To better understand the impact of collaborative online writing with teacher’s intervention in the student’s writing process, we used five data collection instruments (survey questionnaire, individual and group interviews, learning outcomes on formal writing assessments, online analysis of the writing process). The results spotlight the role of collaborative online, with metacognitive prompts from the teacher, on the students’ overall writing quality. We highlight how this collaborative use of technology strengthened their use of metacognitive strategies, feelings of competence in the writing task, and motivation to write.