In the search for optimal terms, keyword databases are very useful, also referred to keyword tool. These list commonly used keywords (search term, either consisting of individual words from word combinations or whole sentences) and show in case of the search engine Overture, the frequency of use. If you enter the keyword "music" into Overture, after about 30 seconds you'll get a long list, which is titled "Search is done in May 2007". Below, the words are arranged according to the number of use. At the top is "music" with approximately 250,000 queries, then "music download" (around 49,000) and "film music" (6,432). This example shows that the keyword databases, a type synonym dictionary, which even considers the relevance - in the sense of the most common use in the search network. The internet offers many databases like this, which sometimes are free. Not only the size of the databases is of importance, but the actuality and other useful information. Google still lists some information about competitors density, the search volume of the previous month and the average search volume and proposes a number of alternative search terms. It makes sense to run the keywords, which were favored by the self-analysis, in multiple databases. This may also help to identify when certain terms are misleading. Keyword databases give general information about the search behavior of potential visitors and customers.