@
GµårÐïåñ and
dhouwn:
I assumed OP meant "ads served by Google", which usually do involve GS and/or G-Adsvc. If these are blocked, then it doesn't seem that blocking IFrames would make a difference either way -- NS will still block them in IFrame. This is why I asked for site examples, to see how they were being served.
@ Vordeller: When you see these, open NS menu and see if other ad agencies are running scripts: doubleclick.net (owned by Google since 2008), yieldmanager, etc. -- Block all ad agencies, and anything not necessary for the site to function.
Check *everything* in NS > Options > Embeddings, including "Apply to whitelisted sites, too." See if this helps. IMHO, it's Best Practice anyway.
Finally, in addition to various ad-blocking software, Firefox has its own simple image-blocker:
Tools > Options > Content > Images. Check "Load images automatically", then in the Exceptions box, whenever you see an image that slipped by NoScript, probably because not served by scripting as
GµårÐïåñ points out, just add the source of the image to Exceptions. Blocked forever, and in a little while, you will have a list of dozens of major ad agencies, without using any bandwidth, subscriptions, downloading filters, etc. To find the source of the image, right-click and "copy link location", then enter only the domain name in Exceptions: "adcompany.com", not the whole link.
RequestPolicy will also block many ads, and its menu will also give you information about where they come from, by right-clicking the page and observing the source or destination of cross-site requests, regardless of whether allowed or disallowed. If they are ad agencies, you can add them to the image list, too, or just leave them default-blocked in RP.