"For the past decade, the LMS market has evolved from providing tools that were purchased at the departmental level to enterprise-class systems purchased at the institutional or even system-wide level. However, since about 2004 the market has been fairly consistent, dominated by Blackboard corporate strategy.
Blackboard went public in 2004, signaling a real market worth of investors' attention. In 2005 – 2006, the market was dominated by Blackboard's acquisition of WebCT, the number 2 player in LMS, resulting in a somewhat extended Department of Justice approval cycle. Starting in 2006, Blackboard was awarded the infamous '138 patent and subsequently filed suit against Desire2Learn, the new number 2 player in LMS. About this same time, open source started to become a viable alternative to proprietary systems in general, and Blackboard in particular, in the form of Moodle and Sakai. From 2006 – 2009, open source became fully established for campus-wide or system-wide LMS deployments. In late 2009, Desire2Learn successfully fended off Blackboard patent lawsuits, ultimately resulting in all 38 claims being ruled invalid by a US Court of Appeals. On the heels of these efforts in 2009, Blackboard purchased Angel, taking another competitor out of the market."
(Phil Hill, 4 August 2011, e-Literatee-Literate)
Fig.1 "LMS Market Share", [http://www.deltainitiative.com/higher-education/lms-strategy]