I decided to share you my knowledges about yahoo optimization, because recently i read many articles about site optimization and with every new line i was discovering new things. It seems that every search engine has it's own rules for optimization, a site might be well indexed on a search engine, and hard to reach on others.
Yahoo has it's own rules and first of it could be the websites with unique content, related to the domain of that site. Sites with articles wrote and designed by human have a big advantage over automated pages, also a big advantage represents the meta-tags; these refer to title, description and keywords of that page. Yahoo likes pages with a clear structure, with as possible less pop-ups. If you have a website and want to know yahoo's opinion about it you can ask a review of your site; there you will find what makes your site valuable than others, and some suggestions how to make it better.
Almost that's what i wanted to tell you about seo on yahoo, if you have any questions please let me know.