I purchased many years ago some keyword domains which I thought where pretty useful and they as well where showing up quite good. Nowadays it looks like they do not so good any longer and all white hat SEO efforts are not getting the expected result. In Arelis IBP9 I encountered that the keywords in the domain should not be over 33% if one wants to rank good in Google. But my domain http://www.billige-mietwagen.de has 100% of the phrase and 50% per keyword, which according to IBP 9 results in being penalized by Google. Is that true? Should I create instead a subdomain http:// other-keyword.billige-mietwagen.de ??