For example; after purchasing a book on Amazon recently I happened to do a Google search on that book and the first thing I see is, "Your book is scheduled to be delivered on..." Aside from the creepy factor I'm left wondering what purpose this serves? I just ordered the book. I KNOW it's on its way.
Turns out they just mined my emails from Gmail to provide it in search results.
I'm sure some developer or product manager thought it would be a cool thing to do without giving any consideration to usefulness much less user privacy. I really don't feel like Google needs to know what I'm buying thankyouverymuch. Gmail account: closed.