Hello, I've noticed that I've recently had a few CPM ad impressions, despite getting an average of about 100 page impressions per day. At this rate, it'll probably take me two years or so until the CPM ad has finished. So, this has me thinking, do I have any guarantee that the CPM ad will even continue to show on my site? Can the advertiser pull it before it gets to 1000 impressions? Also, why isn't it showing more often? What happens if I edit the ads that are displaying on my site - will that risk losing the CPM ad? I'm mainly concerned that the ad is showing to visitors very rarely.
You don't have any guarantee. If you are getting a lot of non-CPM ads, the advertiser may have put such a small dollar amount for the CPM ads that Google is determining that you have a better chance to make more money with normal contextual ads.
The advertiser isn't charged once the impressions reach 1000. They're charged for the impressions shown so far, even if it hasn't reached that number. The advertiser pays based on the impressions shown already for the day. As far as I know, you should get 1/1000 each time the ad shows up. If you were getting $20 for each 1000 times the ad shows up, you should get $0.02 for each impression. On the other hand, if you were getting $0.25/1000 impressions, you should get $0.01 for each 40 times the ad shows up. Now in the last example, if the ad shows up once a day on your site for 40 days, I don't know if you would get that cent, and if so, on which impression you would get that cent.
devin09, when I say "edit the ads", I mean replacing a context ad with a link unit, or something like that, not editing the actual ad's code. So I don't believe that would be a violation of the TOS. Sorry for not being clear about what I meant the first time. Thanks for the responses everyone!
i am still a bit confused about this so hopefully some one can set me straight... i often get channels in my earnings reports stating that i had some CPM impressions and that the eCPM has a particular value (e.g 30 cents) but in the "earnings" column i have a big fat zero. ....do i ever get paid for those CPM impressions? if so, when do i get paid? i am starting to wonder why i ever allowed cpm ads on my sites. EDIT: sorry found the answer to my question: https://www.google.com/support/adsense/bin/answer.py?answer=34242 ---basically the small amounts e.g 0.045 cents are added to your monthly earnings at the end of the month.