Adsense earnings without clicks

Today I checked my adsense reports and realized I had earned 0.01(next to nothing but that’s not the point) but I had zero clicks.
After searching all over the Internet for an explanation I only came back to google adsense help and got the answer I was seeking.

I was under the impression that you did not get paid for ad impressions (excuse the silly pun). Contrary to my belief there are certain ads that do pay for impression. CPM ads as they are known, pay per thousand impression. Silly me.

So there i can still earn with zero clicks

Google explains it here.
https://www.google.com/adsense/support/bin/answer.py?answer=18192&ctx=en:search&query=earnings+without+clicks&topic=&type=f