Moodle
Moodle has continued to evolve since 1999 (since 2001 with the current architecture). It has been translated into over 100 different languages and is accessible in many countries worldwide. Institutions can add as many Moodle servers as needed without having to pay license fees. The Open University of the UK currently uses a Moodle installation for their 200,000 users while the UK government uses a Moodle installation for their Civil Service Learning platform serving half a million employees.