SUMMARY
The popularity of mobile learning and social networking sites has encouraged second language instructors to integrate these technologies into learners’ curriculum. In this study, the learners were supposed to practice in an online jigsaw writing as an extra-curricular activity. They used their imagination and creativity to depict their thoughts using their previous knowledge. The current research had both a qualitative and quantitative phases. From the quantitative perspective, the effectiveness of mobile social networking on EFL learners’ writing ability was examined statistically. In doing so, 60 EFL learners were divided into the experimental and control groups. The learners of the experimental group were also assigned into three virtual groups in which they could help each other to write a piece of writing on pre-determined topics during twelve sessions. Running the t-test indicated that the students in the experimental group could significantly outperform their counterparts in the post-test. Therefore, it could be claimed that mobile social networking as a supplementary strategy had positive effects on EFL learners’ writing ability. In the qualitative phase of the study, a semi-structured interview was conducted in order to explore learners’ attitudes and beliefs about the experiment they had. The responses to the semi-structured interview also revealed that the learners had positive attitudes towards this online supplementary technology-supported writing. The pedagogical implications of the study were discussed and further suggestions were put forward.