Only a click tracker can do that for you TechMan.

I am seeing many referral ad impressions myself in my reports although I am sure I have none.

What click tracker?

google it

Or make 2 channels- A1, A2.

I have channels for pages, channels for colors, channels for ad sizes. Plus of course, url channels.

(I sure wish I had more channels available to me - I have to periodically retire some in order to make room for whatever seasonal site is hitting its peak at the moment)

By using more than one channel on an ad, I can keep a pretty good idea on what is performing - for example, for my main site, I will have four channels for one ad:

a channel that tells me it's a 160x600 ad
a channel that tells me the color (blue/green/red)
a channel that tells me the page (index)
a channel that tells me which site

Then I just write reports that will tell me which pages are performing best, which sizes, which colors, etc.

Nutmeg, that's neat. But wouldn't that entail having hundreds or thousands of channels?
What if you have 500+ pages on your site?

I don't have any one site with that many physical pages (my two "main" sites are database driven; they have over 500 virtual pages, but only four "real" ones) and I try to design/structure them somewhat similarly so I can use the same channels on each, just with different urls. But yea, as I said, I have to periodically retire some channels when they're out of season, in order to make room for others.

(NETmeg)

Ah, that makes sense, NETmeg :)
I have a little over 500 html pages on one of my sites, so I guess that wouldn't work for me.

I found one click tracker "AS Click Tracker" but it doesn't work with new Google Analytics code.

If you're crazy you could number your pages or use a page level and number scheme, again remembering each ad is allowed up to five channel (slot) codes.

You would create the "hundreds", "tens", and "ones" channel, for 000 to 900, and 00 to 90, and 0 to 9, a total of 30 custom channels. By combining these 3 channel codes you have numbers between 0 to 999. Using another channel to identify which site.

Or you could have a page "level" channel 0 (Home), 1,2,3 depending upon how deep your page is in the site's navigation. Then again a page number channel(s) within the level.

Perhaps this is why Google has renamed the javascript parameter "google_ad_slot =" where it used to be "google_ad_channel =" (with old code).

It'd be a lot of work but you could cover a lot of pages and sites. If you were allowed to dynamically generate this combination of "custom channel" codes life would be easier, but technically this is modifying the code Google produced. Obviously some feel changing input parameters is OK. (That's why some avoid the new code).

If you've laid your sites out well with subdirectories, URL channels could help as well, in combination with Level codes and Number codes.

Good Luck!