The word “spamdexing” is from two words, spam and indexing. It refers to a Black Hat SEO technique which utilizes SEO spamming to fool search engines and get high ranking. Spamdexing is a quick or get-fast result scheme to put a website up on the display page. The technique is based on an understanding of the way search engines work and trying to exploit the knowledge.
For example, it is known that search engine crawlers and spiders are attracted to pages with the keyword or search phrase. Spamdexing methods would thus flood the page with a number of the keywords. Most of the keywords would be hidden from the reader. For example, the keywords would be written with the same color as the background, i.e. white on white. While the reader would not notice the crawlers and spiders would, thus give the site a high rating.
Another method is also called baiting. This style has facets of the above mentioned method of keyword stuffing but goes further. It also stuffs the page with popular searched words and phrases even when they do not have any bearing with the page content. The page is thus highly ranked but might contain little, or nothing of relevance about the topic searched for.
Spamdexing is frowned upon because it negates the use of a search engine. A lot of people rely on search engines for links to information. Spamdexing pushes quality links and sites down and stuffs the top with non-useful links. A lot of search engines have lost popularity because of cases like these. Search engines are thus always on the lookout to outsmart spamindexed sites. The trouble is that as soon as they improve on detection techniques the spammers adapt. When the search engines do find a culprit, the age is un-indexed or in some cases, the site is out rightly banned.