A WebmasterWorld thread has complaints from Yahoo Search Marketing advertisers on the conversions, or lack there of, from Yahoo Shopping.
For example, if you do a search on Yahoo Shopping for ipods you may see Yahoo Search ads at the top of the product listings. Here is a screen capture:
As you can see, it takes some scrolling to start seeing Yahoo Shopping results. And some Yahoo Search Marketing advertisers are not happy with their ads showing up in Yahoo Shopping. They want a way to opt out of that Yahoo property.
A WebmasterWorld moderator said, "shopping.yahoo.com provides me with horrible conversions. After about 9 pm EST, all of a sudden I get a barrage of shopping.yahoo clicks and never get any sales." A preferred member agreed, "I agree. I have horrible numbers for shopping.yahoo.com. I want to block them but I can not. The traffic is not good for the campaigns I run."
Control is key for advertisers, especially in online and in search.
Forum discussion at WebmasterWorld.