If a page hosted on amazon.com has security vulnerabilities, users real amazon accounts are at risk because of same-origin policy etc. Putting a page on a diffe

If a page hosted on amazon.com has security vulnerabilities, users real amazon accounts are at risk because of same-origin policy etc. Putting a page on a different domain eliminates this risk. Another reason is for branding. Using aboutamazon.com for PR fluff keeps amazon.com reserved for their actual consumer products.