Pages Yahoo! Wants Included In Its Index:
- Original and unique content of genuine value.
- Pages designed primarily for humans, with search engine considerations a secondary concern.
- Hyperlinks 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.
What Yahoo! Considers Unwanted:
- Pages that harm the accuracy, diversity or relevance of search results.
- Pages dedicated to redirecting the user to another page (doorway pages).
- Multiple sites or pages offering substantially the same content.
- Sites with numerous, unnecessary virtual hostnames.
- Pages produced in great quantities, which have been automatically generated or which are of little value (cookie cutter pages).
- Pages using methods to artificially inflate search engine ranking.
- The use of text or links that are hidden from the user.
- Pages that give the search engine different content than what the end user sees (cloaking).
- Sites excessively cross linked with other sites to inflate a site’s apparent popularity (link schemes).
- Pages built primarily for the search engines or pages with excessive or off-topic keywords.
- Misuse of competitor names.
- Multiple sites offering the same content.
- Sites that use excessive pop-ups which interfere with user navigation.
- Pages that seem deceptive, fraudulent, or provide a poor user experience.
Find out all of their guidelines here:
http://help.yahoo.com/l/us/yahoo/search/basics/basics-18.html
Abdul Malick - SEO and Digital Marketing Blog 