If the advertiser chose the CPM option, there will be images displayed into your ad units, and so you'll earn money even if the visitor doesn't click the ad. Though you may need many thousands of impressions in order to get some decent revenue...
When advertising on the content network you can choose to pay per click, or per thousand impressions. If you got a dollar on no clicks, then you must have been displaying CPM ads.
As noted above advertisers can opt to pay for a thousand impressions of their ad which is why you could be earning revenue without clicks, by far the majority of advertisers work on a CPC basis and you can make far more from clicks than impressions. If you are getting thousands of impressions and no clicks you may need to move/redesign your ad units because its unusual for that amount of traffic not to generate any clicks.
occationaly you will get paid on impressions but thats not in any amount where you need to be concerned of. you get pay per click 99.99999999% of the time
Yeah. Sometimes I get $0.01 from just impressions. But that's with 4000+ impressions a day. So it's not really worth it.
yeah there is a formula for that i guess. you will earn in page impression. but i think there is maximum value before you can earn it.