I've just been around a bunch of machines in our office and they all appear to have the IE Developer toolbar installed. This doesn't make sense for a lot of them. No-one appears to consciously remember loading it. I'm wondering if Microsoft pushed it along with a windows update at some point?
This is a development shop so having some machines with it makes sense. My own machine I know I've installed it on for example. I'm just struggling to find a machine without it to do some testing.