People are getting notifications saying that people have experienced errors when viewing their profile. Clicking on the notification takes you to a page where you're to authorize an application in order to continue.
It failed the sniff test for me, and I quickly found that it's a bogus Facebook application that those folks had inadvertently installed. Perhaps they clicked on the "Activate" button, or perhaps they didn't - I don't remember clicking, and upon subsequent investigation (in the course of writing instructions for another friend on how to remove the "app"), I found that I had it myself!
Removing this app (it's easy):
Just go to "Settings," (top right, near the search box) select "Application Settings," and hit the X next to "Error Viewing Profile" or whatever it's called (I already deleted it ^_^). Since it's a new "app," it should be in the default view, which is "Recently Used."
Aside: I can hear Jaymee cackling from here. This will only reinforce the holdouts' reluctance. =)