Tristan Bishop of Symantec presented yesterday at an STC seminar (I believe he's given the talk before elsewhere) on the advantages of sharing XML content chunks across product. During the talk he mentioned that a large number of their users (50%) simply "googled" for answers instead of using the docs or online help provided with the product.
They then changed their approach to make sure that product information was being picked up by search engines.
Have you found a similar use pattern with your users? We currently restrict the majority of our product information behind a customer-only portal, but if Google is replacing online help and manuals as a source of information and instruction that seems self-defeating.