I think the features that are the most helpful in ePals is the field trip series which allows students to visually go where they may not be able to otherwise. Also, the projects that are ongoing that allow teachers and students from all across the world to communicate about a single topic is awesome because if they're studying something like weather patterns that is different all across the world at a given time, they can share their experiences and learn from each other. I also like the classroom match so that teachers can figure out which classroom corresponds most closely with what they're doing to work together more efficiently.
I think I could use this in my teaching by connecting to another classroom about the subject of measurement. Most other countries use the metric system which is common in chemistry. We could collaborate and learn from another country on how to accurately use the metric system.