Unfortunately, not all web pages contain information that is valuable to a search user. Some pages are created deliberately to trick the search engine into offering inappropriate, redundant, or poor-quality search results.

The following list includes some of the qualities with which Yahoo! does not wish to be associated:

• Pages that harm the accuracy, diversity or relevance of search results
• Pages that direct the user to another page, such as doorway pages
• Pages that change the user’s browser preferences, reset default home pages, resize browser windows, or otherwise interfere with a user's ability to navigate, without permission.
• Pages with automatic software downloads including viruses, adware, spyware, or other self-installing programs
• Pages offering or promoting bulk marketing products or services if the stated or implied use of the product is unsolicited spam.
• Pages with text that is hard to read, such as text that is too small, is obscured by the background of the page, or is located in an area of the page not visible to users
• Pages designed to artificially inflate search engine ranking
• Pages built primarily for search engines or pages with excessive or off-topic keywords
• Pages that seem deceptive or fraudulent
• Pages that are outdated or result in 'product not available' messages