"Quality Score" was introduced in February 2007.
I've taken one month as an example.
2006 average CPC 0.63 3017 clicks ctr 9.3
2007 average CPC 1.25 2600 clicks ctr 6.3
2008 average CPC 2.65 3700 clicks ctr 3.6
2009 average CPC 3.32 2970 clicks ctr 3.7
The net effect of so called quality score is this I get roughly the same amount of licks for 5 times the money and Google shares the 9.3% out amongst 2.5 advertisers each of which are in effect paying 5x. So Google is now getting 12.5 times the income from exactly the same thing simply by introducing quality score.
Cheers
Sid
I think it's a bit difficult to say the rise is purely down to Quality Score anyway - it could be down to more people bidding on those phrases, or people working on their QS to get higher rankings thereby forcing you to pay more to match up to them etc...
Cheers
Sid
Not necessarily but I know what you're saying. More competitors means more chances of some of them having great quality.
Hissingsid, took me a while to figure out where you got that 12.5 times from. You are making assumptions you know nothing about, like this 2.5 advertisers and assuming they pay the same as you.
I manage a few clients. Some have had their costs increase, others decrease and some stayed the same. Many reasons for why but quality score is not the reason.
Just like in natural listings, Google changes the rules - it's their system and their company, they can do this when they like - if you try to work to the rules then you will find that your costs don't increase due to those rule changes (i.e. Quality Score).
I manage a lot of keywords, and managed them through this change - I honestly don't think this was set up as a way to maximise Google's 'take' - in fact if a competitor bids (for example) £1.50 per click I am often able to get a better position and more clicks with a lower bid due to a better Quality Score - thereby REDUCING Google's take