• Original and unique content of genuine value
• Pages designed primarily for humans, with search engine considerations secondary
• Links intended to help people find interesting, related content, when applicable
• Metadata (including title and description) that accurately describes the contents of a web page
• Good web design in general

Unfortunately, not all web pages contain information that is valuable to a user. Some pages are created deliberately to trick the search engine into offering inappropriate, redundant or poor-quality search results; this is often called "spam." Yahoo! does not want these pages in the index.