According to their about page,
Academic Commons is a freely accessible digital collection of research and scholarship produced at Columbia University or one of its affiliate institutions (Barnard College, Teachers College, Union Theological Seminary, and Jewish Theological Seminary). The mission of Academic Commons is to collect and preserve the digital outputs of research and scholarship produced at Columbia and its affiliate institutions and present them to a global audience.
Works in Academic Commons are:
For more information see AC’s FAQ.
Here are some advantages to submitting your work to Academic Commons: