Though I share the opinion that Google, Bing Yahoo etc. are collecting too much information about us and our online habits, I think Internet in it self has grown too much; there's not much we can do for that. That ship has sailed.
However, I'm not too concerned. I have nothing against if they see where I surf and what I search. I'm an old man, happily married to a wonderful and beautiful woman of my dreams, so I don't use / surf adult sites. I do not gamble online, I do not download illegal content.
I do never give my home address, birth date or social security number online. If a site requires this information, there's normally a phone or fax option to use instead. If not, I'll search until I find a site where I can place my order without giving the information online.
I have an alias, an "internet persona" with VoIP phone & fax numbers and email which I read with a different mail client, not using my primary client. I have an Online debit Master Card to use when I order something online, using PO Box shipping address and uploading funds to debit card only when I need to pay something online, and only the amount I need to that purchase, so I don't have to give my real credit card information online and bad guys can not use my card because the account is always empty, funded only when needed.
Google & Co: If you want to collect the information about how I use my computer, please be my guest. I don't like it but there's nothing you can find you could use against me.