M_Bison - 12:21 am on Jun 22, 2008 (gmt 0)

I think we should lower the tone considerably regarding clickthrough data! Such could only be a very small percentage of the ranking algorithm, you're making it sound like the be all and end all of rankings.

Click-through rate is one of the primary drivers determining you position on AdWords, so it makes sense for Google to optimise the organic results in the same way.

As an example, website A is ranking position 10 and website B ranking position 100 on google.com, but website B outranking website A on a regional Google such as google.co.uk.

Amongst other suggestions, the most popular suggestion is that the amount of local links determines the ranking on local Googles. However, through my own experience, I simply have not seen any evidence of this.

A more sensible explanation is that Google is using click-through data.

For example, if I am looking to purchase a new computer, then when searching, I personally am more likely to click on a .com.au result or a TLD result with a local location in the title/meta tags - given I don't know the brand already, hence why yahoo.com may outrank yahoo.co.uk. I also know from my own AdWords experience that click-through rates more than double when using a .com.au domain vs a .com domain in the ad copy.