When talking about key phrases we mean a combination of two to four search words, which are input into the search engine by the user. To get a good ranking by the search engines, it is necessary that these sets of terms are contained in the text of the website. The effective formulation of such key phrases can be created with the help of databases. These services are always linked to costs, because editors sift through and evaluate. But there are also databases on the internet for free interactive research to identify relevant search terms.