Hello Friends,

Yahoo bot is a bit lazy crawl if compared with other search engine spiders and it doesn't crawl into deep of the site to find all of pages to be indexed. Yahoo still pay attention to the keyword and description tags particularly. Try to use relevant Meta tags description and keywords for every single page of your site. Provide sitemap both on your website and with the Yahoo sitemaps function (Yahoo Site Explorer). Well structured website is highly considerable, including site structure. Don't use frames, tables on your web site or at least as less as possible. Site structure should lower percentage in code that it means more content is better.

Thanks