Bad search engine optimisation techniques can get you blacklisted from a search engine. Some techniques that are considered spam are cloaking, invisible text, tiny text, identical pages, doorway pages, refresh tags, link farms, filling comment tags with keyword phrases only, keyword phrases in the author tag, keyword density to high, mirror pages and mirror sites.
While these techniques might work to give you a higher ranking for short time in the long run they will hurt you.Therefore we recommend you rather avoid the following:
• Doing anything to trick the search engines. If what you are doing is not listed as one of the previous “white hat SEO” the search engines will likely view it as spam and penalize you.
• List keywords anywhere except in your keywords meta tag. It is thus not usual to name keywords alone without any other “sentence stuffing”. Search engines know this and will consider you spamdexing.
• Use the same color text on your page as the page's background color. This has been used by some people to stuff their web pages with keywords, which is not a clear practice. Search engines are able to detect this and view it as spam.
• Use the same tag more than once on the same web page, e. g. using more than one title tag.
• Use any keywords in your keywords meta tag that do not relate to the content of your website