Thomson Reuters, creators of the commercial and proprietary EndNote reference management software, have filed suit against the Commonwealth of Virginia and George Mason University, whose Center for History and New Media created the free and open source Zotero reference manager that plugs into Mozilla Firefox.

Thomson seeks ten million dollars ($10,000,000) in damages and an injunction, alleging that their site-license agreement with George Mason University was violated. Thomson claims that a beta version of Zotero is able to convert their undocumented binary.ens file format for citation styling into the open xml-based Citation Style Language (CSL) and that they encouraged their users to perform this conversion, sharing the CSL files with each other and that George Mason University distributed such files. Third parties have commented that one beta version of Zotero was able to read and use .ens files as-is and that the Zotero developers did not implement conversion over copyright concerns.

Thomson's complaint states that GMU reverse engineered or de-compiled the EndNote software and are distributing a derivative of EndNote. Third parties have commented that only the .ens file format needed to be analyzed in order to create this compatibility feature, and that Zotero, a javascript and xul plugin, is quite different from EndNote, a more conventional executable. Thomson further complains that their trademark "EndNote" is used to describe this feature. Thomson requested a jury trial. An extension was recently granted. Thomson discreetly changed their licensing terms for their style files on their website sometime this year, according to the Internet Archive's WayBack Machine. They recently added a click-through agreement for any downloadable content for EndNote.

Update:

 6/4/09 - Court dismissed the suit.  [We'll link to the order when we get it]