Moonlight is a partial re-implementation of Silverlight which is intended by Microsoft to replace Flash as the ‘de facto standard’ for online advertising and video. Moonlight was developed under licence from Microsoft by a group of Mono developers who worked for Novell, but is not implemented on Firefox and is excluded by some Linux distros.
Fedora’s engineering manager, Tom ‘spot’ Callaway, noted that Microsoft’s Covenant to End Users of Moonlight is “specifically worded to apply only to end-users, and makes the following noteworthy distinction: ‘an entity or individual cannot qualify both as an End User and a Distributor for use of the same copy of a Moonlight Implementation.’ It grants no patent rights to Distributors… once you distribute, you stop being considered an ‘End User’ by Microsoft, and are no longer protected by this ‘covenant’ (unless you’re Novell or Microsoft).”