KIDDOM, developer of an online assignment, grading, and communication tool for teachers, has raised $6.5M. Led by Khosla Ventures investment partner Keith Rabois, this round marks the first public fundraising announced by the company. According to Chief Academic Officer Abbas Manjee, the team will use the money to 1) build out a full scale "K-12 operating system" intended to rival the likes of Google Classroom and Summit Public Schools' Personalized Learning Platform, and 2) experiment with "building other tools to better help teachers." Today, the Kiddom team also announced the release of its latest platform iteration, which includes a Timeline feature that keeps track of students' submitted assignments.