Facebook, world's largest social networking site, could become the world’s largest file sharing site too. Mark Zuckerberg and his team of engineers have just added Files to Facebook groups. “With Files, you can share lecture notes, assignments, schedules and many other file types with members of a school group. Anyone in a school group can upload and download files within that group,” according to the announcement from Facebook. Users can upload files up to 25 MB in size and make the uploaded files available to anyone within the group, but music and executable files are not allowed to prevent copyrighted files to be uploaded. E-books, comics, and video files are allowed up to 25MB in size.