Spamming is the use of various techniques which attempt to fool the search engines into providing a higher relevance than would ordinarily be given or to make the site appear under irrelevant searches. The following techniques are likely to be dealt with by having the web site deleted from the engine, penalised or banned.

• Overuse or repetition of keywords.
• Use of keywords that do not relate to the content of the site.
• Use of fast meta refresh.
• Use of colored text on same-color background.
• Duplication of pages with different URLs
• Use of different pages that bridge to the same URL

If you try to use these spamming techniques the search engines are likely to pick up your pages automatically. However some might slip through. Other webmasters will be likely to report your pages to the search engines who will then punish them. It's not worth it.