Firefox 3.6 brought the world Personas. I’m not against them; people really like that kind of thing. I am 100% against the mouseover-to-preview functionality, though. Combined with the fact that they are now shoved in your face and that it’s not trivial to disable it, I’ve lost a little faith in Mozilla.
Fortunately, there are a couple of things a person can do.
Go to Tools — Options (Firefox — Preferences on Mac OS) and
click the Security icon. Click exceptions, and then remove “getpersonas.com”
from the list. This will disable Personas until they are moved to another
domain (which is planned).
It is possible to edit your profile and disable the “LightWeightThemeManager,” some options are discussed here: MozillaZine Forums.
In order to simply things and vent, I made Zero Personality to disable Personas.
Remember when Firefox was the browser without the crazy bloat? Glenn Beck and I do.