It’s birthday is this week if I am correct on my dates.
You can search and view DWF files on the web all without installing a single application. 2D or 3D does not matter as CADoogle uses Autodesk Freewheel to display the views of DWF files in any Java supporting browser. I even found my own neighborhood all detailed out in DWF format by the local county planning department.
http://www.cadoogle.com/
CADoogle Mobile
http://cadoogle.com/mobile/