by Rob Sullivan
http://www.enquiro.com

By now you've probably heard that BMW.de was removed from the Google index for spamming.

They were using a combination of Javascript and Doorway pages to rank for terms they shouldn't have ranked for (such as used cars).

What BMW.de was doing was creating a bunch of doorway pages with no useful content at all, and optimizing them to rank highly for terms. A search engine crawler would index the content and since crawlers can't execute javascript they would merely index the page.