BigBlueButton is an open source web conferencing system developed primarily for distance education. BigBlueButton supports multiple audio and video sharing, presentations
with extended whiteboard capabilities – such as a pointer, zooming and drawing – public and private chat, desktop sharing, integrated VoIP using FreeSWITCH, and support for presentation of PDF documents and Microsoft Office documents. Moreover, users may enter the conference in one of two roles: viewer or moderator.
