Hi, welcome to DaniWeb. There are two different ways to sell advertising. When advertising is sold on a CPM basis, that is cost per thousand impressions, and there is a fixed rate for every 1,000 impressions. When advertising is sold on a CPC basis, that is cost per click, and money is made only when ads are clicked on. Google AdSense follows the CPC model. There are other ad networks and ad agencies such as Tribal Fusion, ValueClick, Burst!Media, etc. which operate on the CPM model.

So with Google Adsense it wouldn't matter if I had 10,000 Page Impressions per day if I get no clicks then I wouldn't make a dime?

I read that with Google you can't have any adds from another source like you mentioned. How are you able to do this. I see that you have adds from DoubleClick on this site as well as Google Adsense...how are you able to do this? Is it because I see you are only showing 1 site's adverts on a page...like you don't have Google & DoubleClick on the same exact page, but do have on the same site.

If that is so what I said above then that would be good since a person could mix the adds up from different sites so that we get Page Impressions as well as clicks.

Yes, regardless of the number of impressions, you only get paid when someone clicks on an AdSense ad.

You CAN run AdSense side by side with other advertisements. You simply can't run it on the same page at the same time as other "contextual ads" which basically means any direct competitor type ads, such as Yahoo's Publisher Network, which is basically the exact same thing as AdSense but by Yahoo instead of Google.