When does Bing or Yahoo anonymize your search data? When does Joe's Random ISP delete your email from all their tape backups after you cancel your account? Google is being honest and open about what they do; other companies hope you don't realize you should care.
Actually, you only have to trust them for 9 months after you decide to stop using Google:
http://www.google.com/policies/privacy/faq/
When does Bing or Yahoo anonymize your search data? When does Joe's Random ISP delete your email from all their tape backups after you cancel your account? Google is being honest and open about what they do; other companies hope you don't realize you should care.