Évitez le texte ou les liens cachés. N’utilisez pas de pages masquées (”cloaking * “) ou de redirections trompeuses.
* N’envoyez pas de requêtes automatiques à Google.
* Ne multipliez pas les termes sans rapport avec le contenu réel de votre site.
* Ne créez pas plusieurs pages, sous-domaines ou domaines présentant un contenu en grande partie identique.
* Ne créez pas de pages qui installent des virus, chevaux de Troie ou autres logiciels espions.
* Évitez les pages satellites (”doorway”) créées exclusivement pour les robots de moteur de recherche ou d’autres solutions telles que les programmes d’affiliation sans véritable contenu informatif.

Source Google.com

* définition du terme cloaking et doorway sur wikipedia :
“… Cloaking is a black hat search engine optimization (SEO) technique in which the content presented to the search engine spider is different from that presented to the users’ browser. This is done by delivering content based on the IP addresses or the User-Agent HTTP header of the user requesting the page. When a user is identified as a search engine spider, a server-side script delivers a different version of the web page, one that contains content not present on the visible page. The purpose of cloaking is to deceive search engines so they display the page when it would not otherwise be displayed. … “

“… Doorway pages are web pages that are created for spamdexing, this is, for spamming the index of a search engine by inserting results for particular phrases with the purpose of sending you to a different page. They are also known as bridge pages, portal pages, zebra pages (a humorous arbitrary coinage by Jill Whalen of High Rankings Advisor), jump pages, gateway pages, entry pages and by other names. Doorway pages that redirect visitors without their knowledge use some form of cloaking. …”