The Groups tab allows you to view groups of which you are a member. These groups are separate from CAS groups, and enable your school to coordinate the extracurricular activities themselves. Groups are useful for organizing sports teams, extracurricular clubs, and even temporary events like a service event or fundraiser. Groups can send messages, share photos and files, coordinate their calendars, create shared to-do lists and more. Groups can also be used by Extended Essay Advisor and TOK teachers to coordinate their students and collect drafts and essays. For more info about these uses check this blog.