Chalk It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are then consolidated and compressed during diagenesis into chalk rock. Most people first encounter the word "chalk" in school where it refers to blackboard chalk, which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased. Blackboard chalk manufacture now may utilize mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum (calcium sulfate). While gypsum-based blackboard chalk is the lowest cost to
Blackboard Inc. the CourseInfo brand was dropped in 2000. As an extension of CourseInfo's original two weeks for free courses, the company provided a hosted version "CourseSites" for teachers to try out for free. After having raised its seed round, the new company made a profit in its first year, and its sales in 1998 approached US$1 million. Other early products included Blackboard Classroom and Blackboard Campus both derivatives of the original platform. In 2000, Blackboard acquired iCollege/College Enterprises Inc.'s campus card, introducing commerce capability to Blackboard's portfolio. By 2006, the firm's learning platform software was used in more than 40% of