User name colors

I was wondering about the significance of the different user name colors that are there now...
This far, there was only green for people who bounce mail (quite unfitting imo, red would be much better there), but now there are also other colors like purple, and there are also names in bold...
So what's the meaning of this all? :?

Thanks for sharing your opinion. Sorry, red is reserved for the divine admins.

As for the colours of usergroups:

that only works on the top 3 styles, also i see advisor usergroup in the style default color.

firefox 1.0