During the week commencing July 23rd, 2007, we are introducing a new ranking model in the UK that considers an ad's quality and bid amount. The new model is designed to help you spend less time in bidding wars with other advertisers and more time creating the most relevant, effective ads, which can help drive better results for your business.

Here's a quick summary of this important 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.

We're excited to announce that the new ranking model is now live in our UK market. The new ranking model is designed to improve user results through higher quality search ads. When users engage with these higher quality search ads, advertisers will receive more interested, valuable potential customers, helping to drive better results for your business.

As we previously announced, both bid amount and ad quality
now determine an ad's rank in search results.

Your bid is the maximum amount that you're willing to pay when your ad is clicked. You will never be charged more than this amount.

Your ad's quality is determined by:

The ad's historical performance-determined by its click-through rate relative to its position on the page.*
The ad's expected performance, relative to competing ads displayed at the same time-determined by various relevance factors considered by Yahoo! Search Marketing's ranking algorithms.

- Yahoo!