Chalk produce, and thus widely used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, and is marketed as "dustless chalk". Colored chalks, pastel chalks, and sidewalk chalk (shaped into larger sticks and often colored), used to draw on sidewalks, streets, and driveways, are primarily made of gypsum. Chalk is a source of quicklime by thermal decomposition, or slaked lime following quenching of quicklime with water. In southeast England, deneholes are a notable example of ancient chalk pits. Such bell pits may also mark the sites of ancient flint mines,
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