I'm taking the plunge on Conversion Optimizer after having consistent CPA at around $30 for several years (I market a software product that retails at $50/month).
I figure that if Google can deliver more leads at $30, then I can up my budget as it will likely be ROI positive for me.
So far, the only weird thing is that Google says I have a consistent $30 CPA historically, but recommends I set my max CPA at $45. That's a head-scratcher for me, but I'm willing to give it a try.
Much appreciated if others can share their experiences and I will post updates and provide thoughts on campaign performance.
Here are a few info sources discussing advertiser reactions to and trials of the technology:
1) Search Engine Watch Forums discussion [forums.searchenginewatch.com] on C.O. - note specifically posts #30, #35 and #15 as they are all experienced SEM managers.
2) Webmasterworld thread [webmasterworld.com] - (there are a few reviews based on testing, as well as discussion about how to use C.O. to do CPA Steering)
3) A niche site operator's review of it [microisvjournal.wordpress.com] after trying it
4) Another review [ppcdiscussions.com] of and results from using C.O.
A big part of its optimization is to figure out which components of Google's search and content distribution networks do and don't convert for any particular advertiser, but I would argue that those targeting decisions are best made by someone other than the search engine who stands to profit from broader distribution.
So far, one day in, my experiences are similar to what I've seen in some of the anecdotes you have pointed my way. Google recommended a CPA much higher than my historical CPA and (within 24 hours at least) haven't performed. But my product has fewer conversions and a higher price point than much of what I've seen here.
Frankly, I'm kind of surprised that there isn't more discussion on conversion optimizer. Maybe it's because Google has tucked it away as a link in campaign settings and has only mildly promoted it. I'd be curious to know if there are serious numbers of advertisers using it.
Either way, I'll post updates as I have them and would be interested in others experiences as well, especially in how to make the most of the feature.
