In case you didn't read the story, this title isn't accurate. ReadWriteWeb printed a retraction: Messages for those members with profiles that are already public will become public. Everyone else will have the option of making their statuses public.
In my little corner of FB people are already reporting seeing things that they never did before (e.g. status updates and photos from cow-orkers). If FB screw this up there will be a huge backlash.
If FB screws this up there will be a huge backlash for a few weeks, then FB will apologize. FB screws up with some regularity, but they check themselves quickly afterwards.