BigBlueButton

BigBlueButton is an open-source web conferencing system built specifically for online learning. It's designed to integrate seamlessly with Learning Management Systems (LMS) like Moodle, Canvas, and Schoology. Features include multi-user whiteboards, breakout rooms, real-time polling, shared notes, emoji reactions, and full recording/playback. It supports large classes, with scalability determined by server capacity when self-hosted.

Its target audience is educational institutions and corporate training departments. It scores well for its deep pedagogical features, no licensing costs, and strong community development. The ranking reflects its niche excellence in education, though it requires technical resources for hosting and management.