Late last week there was a thread started on the topic of Google's Search Spam Reporters. This thread sprung up an interesting technical detail about Yahoo's URLs and what one attribute in the URL means.
Danny Sullivan writes that when you do a search on cars in Yahoo! Search, you will find that in the number one slot is Cars.com. Danny pulled out the URL in the SERP which reads http://rds.yahoo.com/S=2766679/K=cars/v=2/SID=e/l=WS1/R=1/SS=2044565/H=1/IPC=us/SHE=0/SIG=10pe5sku9/*-http%3A//www.cars.com/
Danny says "H=1 seems to indicate the site was hardcoded to show up in response to this query. In contrast, H=0 means no hardcoding appears to be involved."