Just got a call from a client who discovered that his cost per click had gone up by a factor of 12 overnight, from $6.50 to $88.00 per click.
Ordinarily, a leap this big is due to quality score. Like Google really hates your website. But the client mentioned in his message, "Quality scores are good or excellent."
So I called back about 15 minutes after getting the message, basically expecting to not know what to do except contact AdWords help and make a lot of noise.
When I reached him, the problem had been solved. Turns out he had switched on Conversion Optimizer, and so he was now looking, not at a cost per click (CPC) column, but at a cost per action (CPA column). Instead of $6.50 per click, he was getting $88.00 per lead.
So if/when you move a campaign to Conversion Optimizer instead of CPC bidding, follow this advice:
1. Download a copy of the campaign into AdWords Editor, so if Conversion Optimizer wreaks havoc you have a Time Machine to bring things back to the way they were.
2. Take time to familiarize yourself with the new dashboard and metrics, so you don’t freak out when the usual numbers go haywire.
As Billy Joel sings, "Everyone goes South, every now and then…" ;)