ePals is the social network optimized for K-12 learning. Over half a million classrooms in 200 countries and territories have joined the ePals Global Community to connect, collaborate and exchange ideas. ePals now translates in 35 languages!
The benefits of the site are that the students can connect with other students and classrooms around the globe. You connect with them by the projects that you are working on in the classroom. This gives the common ground to talk about back and forth.
The possible pitfalls are if you get a classroom that is not as involved as yours. It could be a let down and you may have to find another classroom that you could connect with.