At Volkswagen they use Internet Explorer 6:
The Volkswagen Group is using Microsoft Internet Explorer 6 as standard the for displaying web pages. For the daily work with our platform, we recommend you to use the Microsoft Internet Explorer 6, too.
And they recommend you to do same for security reasons:
For security reasons, the Volkswagen Group does not recommend other browsers like Mozilla Firefox, Opera, Netscape etc. as they show security gaps.
Update: The webpage was last modified on October 19th, 2011
Update 2: While the meta date is from October 20th, 2009