Hey do you mind if I move this out to the Questions, Problems, Suggestions board? It might help if everyone knows what this is about.
The "nothing, or nothing you can see" message that shows on the online page is a similar thing. It means that person is either viewing a page the software doesn't quite recognise, or they could be checking some of their profile settings (which in the case of their personal profile settings would be "nothing you can see"), or it could be a staff member checking something in admin (which you can't see either).
Bottom line is they are harmless messages, even if the phrasing is a tad geeky, so don't worry about them.
Devious, treacherous, murderous, neanderthal, sub-human of the West.