Upcoming system change:
As you know, we continuously work to make our ads system more accurate in order to further improve the effectiveness of your advertising campaigns. Among other ongoing improvements, we are refining our ads delivery system to better reflect the goals of our advertisers. This change will take place over the next few weeks and, assuming current bids remain unchanged, will mean that:
CPC advertisers (advertisers who have chosen to bid “cost-per-click”) may receive more clicks.
CPM advertisers (advertisers who have chosen to bid “cost per thousand impressions”) will continue to receive impressions but may receive less clicks.
Do I need to do anything?
As a CPM advertiser, you are indicating to our system that it's more important that your ad is seen by your audience rather than clicked i.e. you have chosen to pay for impressions, not clicks. If your main objective is to increase awareness of your business with an ad impression, there is no need for action. However, if your most important objective is to drive clicks on your ads, you should change your bids from CPM to CPC.