Well I was standing in the shower this morning thinking about my PPC campaigns (I'm a sad little man) and I came up with the following observations.
I am, by no terms, an internet expert, but I have been doing PPC for some time now on a number of diverse web sites. My initial impression is that overture doesn't produce as many clicks, but they do have a higher conversion of impressions to clicks. As such, I wonder if this is a factor of how the set up your overture bids as opposed to google.
With overture you can see who is bidding and the bid price within your keyword bid pricing stage. I beleive that this approach limits the amount of clicks from others besides your target audience (web masters, competition, etc.). BTW, as a pirate at heart, I follow a the code of "honor among theives" and don't click on competitor ads.
I tend to beleive that these unwanted clicks are more prevelant than than we think and while at $.10 a click, it may not be that bad, but if you have $2.00 to $4.00 per click it may start to sting.
Further, I think what Adwords is trying to do with their placement formula is admirable, but I would rather choose were I want to be, knowing what I'm paying. In the long term bad ads will be removed by their owners and good ads will rise to the top.
I'm sure this has been said before, I thought I'd give my take.
My initial impression is that overture doesn't produce as many clicks, but they do have a higher conversion of impressions to clicks.
Another month has passed and I can still confirm that Overture gives better conversions than Google, but for absolute numbers, Adwords gives 2-3 times as many conversions. And for us, business.com consistently does slightly better than Overture. You need the cheaper, converters to keep the overall CPA figure down.