The key paragraph from George Mason University's response to the Reuters lawsuit, via Dan Cohen:
The Thomson Reuters Corporation has sued the Commonwealth of Virginia over Zotero, a project based at George Mason University’s Center for History and New Media (CHNM). A free and open-source software initiative, Zotero aims to create the world’s best research tool and has already been adopted by hundreds of thousands of users at countless colleges and research universities. CHNM announces that it has re-released the full functionality of Zotero 1.5 Sync Review to its users and the open source community. As part of its formal response to this legal action, Mason will also not renew its site license for EndNote.