This study investigates the linguistic and pedagogical bene?ts and challenges of using a digital annotation tool (called Perusall) to facilitate second language (L2) reading in an advanced English language course at university level. The goals of the study are to analyze the students’ reading and annotating behavior, examine the effects of social reading on their un-derstanding of English for science and technology texts and investigate how an L2 teacher might effectively incorporate this activity in his/her classroom. The results indicate that students spent an above average amount of time reading (compared to that reported in the literature) and that most students completed their reading assignments before class with the Perusall platform. Moreover, they predominantly used the social reading experience to summa-rize the sections of the long article, and query fellow students about the meaning of difficult and transitional sentences. Perusall allowed students to co-construct meaning and scaffold their learning while engaged in close readings of the science and technology texts outside of the physical class-room. Drawbacks of social reading in this environment are primarily others’ comments impeding some students’ understanding of the text and students‘ frustrations with some technical aspects of the Perusall tool. Pedagogical suggestions regarding L2 social reading include better integrating students‘ virtual comments into classroom discussion/activities, and offering more structure for students.