In a blog, Google software engineer Matt Cutts said that Google had removed BMW's German site from its Web index after the site included "doorway pages" that would automatically redirect visitors to a different URL.
Cutts explained that when Google's crawlers visited a BMW page, it saw blocks of text with repeated key search words such as "neuwagen," which means "new car" in German. However, when a user visited the listed page they would be with less text and more pictures, which was more attractive than the page the crawler saw, but would have scored lower in Google's PageRank system.
"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' blog said.
BMW may also have to disclose details of who created the doorway pages--and assure Google "that such pages won't reappear on the sites"--before the domains can be reincluded, Cutts said.
The German site of technology product vendor Ricoh is also due to be removed from Google "for similar reasons," Cutts said.
BMW and Ricoh were unavailable for immediate comment.
Tom Espiner of ZDNet UK reported from London.