Comment 14 for bug 147230

I vote to have it disabled by default.
New users that I have introduced to Ubuntu get really lost the first time that they scroll the mouse on the desktop (which is often an undesired scroll, nobody thinks about scrolling to change the workspace when they don't even know what this workspace thing is...)
It should however be simple to activate, as I am sure that people that have grown accustomed to using it will be very vocal about having it disabled.

This is obviously one of the advanced uses of the desktop, you can always change workspaces by clicking on the lower right mini-workspaces. That way you can still start using the different workspaces.