Summary: Blackboard, a maker of proprietary software for Web-based course management, has patented many of the elements of its software, apparently hoping to discourage competitors. The Software Freedom Law Center, on behalf of the developers of three free-software course-management systems (Sakai, Moodle, and ATutor), has asked the United States Patent and Trademark Office to reconsider whether the patents were rightly granted, in the light of the very extensive prior art, which is described in the Wikipedia entry dealing with the history of virtual learning environments.