I know that in Argentina and Uruguay they still use the Vd form. In Mexico I don't think (except for certain professions) it is taught at all. In Cuba, Domincan Republic speaking Vd. to someone under 30 will be met with strange glances.
I do understand that Spanish is fairly universal, but I still think (and the point to my post) is that in order for .lrn (and OpenACS) to be successful, locales need to be enabled.
If anything, to my mind, everything should be in Ud. and NOT Vd. That way it shouldn't offend anyone!