Research has revealed how actively contributing to online communities can advance technical skills, knowledge, and confidence, and ideas for sustaining and evolving participation. However, recent studies have also shown that contributors of online content are a small subset of the population using technical systems, and that this subset is not representative of the larger population. This trend is concerning both in terms of who takes advantage of opportunities to develop technological competencies necessary for participation in the 21st century, and in terms of who is authoring content that informs public opinion and knowledge. In this paper, we consider how Latino youth interact around online digital artifacts and how we can design features to better support their contributions of communication and critique. This work specifically attends to documented trends in formal learning environments in Latino communities, including emphasis on good behavior and respect for adult authority and less emphasis on individual autonomy. We focus on a collaboration with a seventh grade teacher using an online platform in a predominantly Latino middle school. We first describe student online communication and contribution, using qualitative ethnographic case studies and quantitative log data. We then share the collaborative design of reactions, a feature encouraging student contributions in the form of communication and critique. Findings suggest important cultural and pedagogical design considerations for online social learning network interfaces aiming to build learning community and engage diverse youth populations to contribute.