Campaign Update : CPC vs CPM

It was running fine until this morning. When I felt that the clicks coming are not enough, I made some changes to the
ads that I posted earlier.
The only changes that I remember that I made were, changing the targetting for the ad from english speaking to include all American users. Thus suddenly after an hour or so I got my ads disapproved.
Well although I had received only 3 clicks out of 31k impressions it was really fun to learn some importance of CPC over CPM type of traffic.

Till last night I was of the impression that CPM is better than CPC and is a safe bet.
But actually speaking the CTR plays a vital role in deciding the importance of a method used in affiliate marketing.
If the CTR is very less say 1-2%, then using CPM will take you to the end of life for your credit card.
E.g Consider myself having $0.35 as CPM and $0.35 as CPC. For the above ad I used CPC, and for 3 Clicks I was charged about $1.02.
Say If I had used CPM as my method of promotion then I would have incurred a total charge of 31K/1000 * 0.35 = 32*0.34=$10.88 a total of $9.68 over my CPC cost. SO its always better to bet on CPC than on CPM.