The official Yahoo Search Blog has a post which is in response to all the comments and queries they received over their new Blocked Domains feature.
"To reiterate: Your Sponsored Search and Content Match ads can be displayed outside of Yahoo.com and other areas of Yahoo! They can appear throughout our partner distribution network. The Blocked Domains feature lets you specify websites or sections of a website in our partner distribution network where you donĂ˘â‚¬â„˘t want your ads to appear. At its core, Blocked Domains is a tool to help give you more control over your traffic from your paid search and content match ads.
To clarify: You can block up to 250 domains. This doesnĂ˘â‚¬â„˘t mean that there are exactly 250 domains that you should block, or that there are just 250 domains in our partner distribution network. It means that you have the option to block up to 250 domains of your choice. At this time, however, you may not block IP addresses, Yahoo! domains, or opt out of the Yahoo! partner distribution network as a whole. Also, we do not make available a list of all Yahoo! distribution partnersĂ˘â‚¬â€ťthere are simply too many, plus the list is ever-changing.
Blocked Domains goes hand-in-glove with the pricing discounts we announced in June. Before adding these pricing discounts, you were charged the same amount per click regardless of whether the traffic came from a Yahoo! page or a site in our distribution network. Pricing discounts enable you to be receive a discount for certain clicks, depending on our assessment of the quality of traffic from our partnersĂ˘â‚¬â„˘ sites. Typically, these discounts range from 5 to 15 percent.
Tips and Tools
Getting back to Blocked Domains, there are some sites, such as those of your competition, that you may want to block for obvious reasons. You may also want to keep your ads from appearing on sites that you know wonĂ˘â‚¬â„˘t appeal to your prospective customers, or on those with which you do not want your brand associated.
To determine which sites or pages may not be performing the way you want based on your business goals, you should review the data from your web server logs, account reports and other account data.
For more info on how to read your web server logs and on tracking URLs, visit the Help Center.
In addition, you may also want to consider using a third-party analytics package to help you determine which URLs to block. There are many tools available. Larger firms may wish to consider hiring a third-party consultant to run analytics, determine any URLs to block, and so forth. Yahoo! Search Marketing offers an Ambassador Directory of firms that have proven proficiency in Yahoo! products and services."