Love the concept; but replaced a few other favicons Rated 4 out of 5 stars
I used a different, previous add-on with earlier FF versions to generate/select my own FavIcon for sites (can't remember name) which doesn't work with FF9.0.1, so tried this one.
Works well EXCEPT replaces a few of the favIcons I previously selected for the other sites. I like the colorful "neutral" favicons it uses, however, because the generic box was so unhelpful in organizing my bookmarks toolbar.
Firefox API does not provide any means to tell where a favicon comes from. E.g., I cannot tell if it uses the generic icon or some other, which was manually set by another extension. You can, however, add the domain of these sites to the exception list in IdentFavIcon options, thus telling the add-on not to generate icons for them. HTH.