In My Dianomi each ad variant has a ‘Score’. This is a function of Click Through Rate (CTR) and Cost Per Click (CPC). Ad variants with higher Scores will be shown more frequently.
Click Through Rate (CTR) is calculated from the number of clicks and total impressions. As a general rule of thumb, the more general your content, the wider your audience, the higher you can expect your CTR to be. If you are targeting a more niche audience, CTRs will be lower so it may be necessary for niche ads to pay a higher Cost Per Click. CTRs and Scores can be seen in Analytics.
We recommend starting with a higher CPC and lowering it if the CTR is good and the campaign is pacing well, rather than starting with a low CPC and raising it if the campaign does not attract many clicks.