Answers to some of the thousands of questions asked by marketing executives who attended the AMA's first free Web seminar, "Why Can't My CEO Find Our Website??"
In the search engine world, spam is defined as the manipulation of a web page to give it an artificial boost in the search engine rankings. Generally, spam is what the search engines say it is. I.e., it is defined by the search engines themselves. Each of the major search engines provide specific guidelines describing what webmasters should and should not do to their web pages in order to achieve a better search engine ranking, though that has not always been the case.
Several methods are universally deemed search spam, including hidden text, doorway pages, and mirror pages.
For engine-specific guidelines, visit the search engines themselves.
Yahoo! > Search Help > Search Spam & Deletions provides information about what search engine optimization tricks to avoid on Yahoo! and on Alltheweb, which will soon be powered by Yahoo!.
Google Information for Webmasters provides information about what techniques to avoid on AOL, Google and Netscape.
AltaVista - Help - Adding & Removing URLs provides information about what techniques to avoid for AltaVista. Just search the page for the word spam by selecting "Edit > Find (on This Page)... Ctrl+F" in the browser menu.
If you find a website using any of the search engine optimization tricks mentioned here, we encourage you to report the spam.
See also: Web Spam Taxonomy. Gyongyi, Zoltan; Garcia-Molina, Hector. Web Spam Taxonomy. Technical Report, Stanford University, 2004.