The Ad quality algo that Yahoo have been testing recently in certain verticals in the UK now has an official arrival date set for the 23rd of July.

A an e-mail from Yahoo to UK advertisers summarises the change –

• Both bid amount and ad quality will determine an ad’s rank in search results the week commencing July 23rd, 2007.

• This will replace the current method, in which ads are ranked by bid amount only (bid-to-position).

• This is designed to allow you to focus less on competitive bidding practices and more on the quality of your ads.

• By improving the quality of your ads and making them more relevant to users, you may be rewarded with a better ranking and/or a lower cost for your ads.

How is ‘ad quality’ determined?

1. The ad’s historical performance – its click-through rate relative to competitors and normalised for position.

2. The ad’s expected performance – determined by various relevance factors considered by Yahoo! Search Marketing’s ranking algorithms, relative to other ads displayed at the same time.

Overall ad quality is displayed in a graphical form by the quality index.

You can learn more here at Yahoo.