Flasche

Copyleft the savior of Open Source --- Copyleft (a play on the word copyright) is the practice of using copyright law to offer the right to distribute copies and modified versions of a work and requiring that the same rights be preserved in modified versions of the work. In other words, copyleft is a general method for marking a creative work as freely available to be modified, and requiring all modified and extended versions of the creative work to be free as well.