Google has blacklisted BMW.de after the carmaker's German site violated Google guidelines by using doorway pages that automatically redirect visitors to a different URL - a technique that can artificially boost search engine rating - reports CNET, citing Google engineer Matt Cutts's blog. Though Google crawlers would see blocks of text with repeated keywords, visitors to the page would be redirected to a well-designed, graphically rich page without the text.

"This is a violation of our Webmaster quality guidelines, specifically the principle of 'Don't deceive your users or present different content to search engines than you display to users,'" Cutts wrote in his blog.

BMW.de has already removed some of the redirect pages. To regain Google listing status, BMW may also have to disclose details of who created the doorway pages.