Google knows all.
Google has every e-mail you ever sent or received on Gmail. It has every search you ever made, the contents of every chat you ever had over Google Talk. It holds a record of every telephone conversation you had using Google Voice, it knows every Google Alert you've set up. It has your Google Calendar with all content going back as far as you've used it, including everything you've done every day since then. It knows your contact list with all the information you may have included about yourself and the people you know. It has your Picasa pictures, your news page configuration, indicating what topics you're most interested in.
And so on.
Not as bad as Facebook.
Facebook has even more interesting stuff: your pictures, your comments, your likes, your friends, your un-friends.
Thankfully, we ain't in America, so, look up the "Right to Be Forgotten", it allows us to, supposedly, get our stored information deleted. Just don't hold you breath.
Have a nice day.