Project Butterfly is an Autodesk Technology Preview of a cloud computing solution that enables AutoCAD users to edit and collaborate on AutoCAD drawings through a Web browser. With Project Butterfly, AutoCAD users can share and work on DWG files with colleagues and clients from any computer with an Internet connection. Users don’t have to have AutoCAD installed, nor do they need a Butterfly account to access this preview.

http://labs.autodesk.com/technologies/butterfly/