In recent years, the terms white hat and black hat have been applied to the Search Engine Optimization (SEO) industry. Black hat SEO tactics, also called spamdexing, attempt to redirect search results to particular target pages in a fashion that is against the search engines' terms of service, whereas white hat methods are generally approved by the search engines. White hats tend to produce results that last a long time, whereas black hats anticipate that their sites may eventually be banned either temporarily or permanently once the search engines discover what they are doing.