I received the following hint via email from Dan, which repeats a hint he posted on his blog. Here's how Dan removed Flash banner ads in Chimera (and Mozilla and probably Netscape as well). Please note that "I" in the following section refers to Dan, not me!
I managed to disable those annoying Flash banner ads in Chimera (I most often see them on Wired.com). Since you probably don't have one, create a file called userContent.css in your Chimera user chrome directory, which is located at ~/Library -> Application Support -> Chimera -> Profiles -> default -> random -> chrome. Replace 'random' with the name of the directory, which is usually a string of random characters followed by '.slt'. In the new userContent.css file, enter the following:
/* this hides the usual 468x60 Flash banner ads */Now restart Chimera and it should work.
embed[type="application/x-shockwave-flash"][width="468"][height="60"] {
display: none !important;
visibility: hidden !important;
}
/* this hides the not so usual but very annoying 728x90 Flash banner ads */
embed[type="application/x-shockwave-flash"][width="728"][height="90"] {
display: none !important;
visibility: hidden !important;
}
Mac OS X Hints
http://hints.macworld.com/article.php?story=20021127061854547