Project Butterfly is an Autodesk Technology Preview 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 DWGTM files with colleagues and clients from any computer with an Internet connection.
Share drawings with other people. View and edit DWGs without downloading any software, using just a Web browser.
Invite your project team to an online meeting where all sides can discuss and co-edit a drawing in real-time. Or browse through comments and changes on your own time.
Use Project Butterfly to collaborate with colleagues and clients. Anyone can access Project Butterfly, even if they don't have AutoCAD installed, and even if they don’t have a Project Butterfly account.
I tried it out and I must confess the solution is very impressive despite the fact that this is still in 2D.
I found very promising comment from SolidSmack webpage:
Thanks for spreading the word about Project Butterfly.At this point it is indeed 2D. You may recall that Project Freewheel is our technology preview to investigate viewing and sharing of 3D models via the web. So it is quite possible that something could happen in the future - no promises - but we are not ignoring 3D. Project Butterfly is based on RealDWG technology so the plumbing for 3D is available.
Can't wait to see more web-based CAD solutions.