Yahoo very conveniently gives us a whole list of things that they frown upon on:
Some, but not all, examples of the more common types of content that Yahoo! does not want include:
• Pages that harm accuracy, diversity or relevance of search results
• Pages dedicated to directing the user to another page (doorway pages)
• Multiple sites or pages offering substantially the same content
• Pages that rely heavily on content or links to content created for another web site, such as affiliate content
• Sites with numerous, unnecessary virtual host names
• Pages in great quantity, automatically generated or of little value (cookie-cutter pages)
• Pages using methods to artificially inflate search engine ranking
• The use of text or links hidden from the user
• Pages that give the search engine different content than what the end user sees (cloaking)
• Sites cross-linked excessively with other sites to inflate a site’s apparent popularity (link schemes)
• Pages built primarily for the search engines or pages with excessive or irrelevant keywords
• Misuse or inaccurate use of competitor or brand names
• Sites that use excessive pop-ups, install malware (i.e. spyware, viruses, trojans), or interfering with user navigation
• Pages that seem deceptive, fraudulent, or provide a poor user experience
So now you know!
