Opt Out? Oh, but you can.
Try Blur (the latest emanation of Adine's Do Not Track application).
It plugs into your web browser as per usual, but with some subtle differences which work much better than in previous versions.
Now, when a site asks for your email address, Blur very graciously creates a brand new email address (I suspect hosted by Adine, someplace) and inserts that email address instead. Mail sent to this masked email address is then forwarded to you (or not, as you choose). You can also see who is using that email address, how often it is used and then decide when to stop receiving mail from it.
The site you signed up with will never, ever see your "real" email address or store it in their records. And you can TURN OFF THIS FORWARDING WHENEVER YOU WANT.
Down right elegant, if you ask me. No more creating and trying to remember those throwaway mail addresses, wondering who is using what and where, worrying about who stole that company's email database, etc. Life on the internet just became good again.
They also mask credit card details during purchases, mask and store your site passwords, block tracking cookies and do various other wondrous things should you care to pay for the subscription, something I might actually do as I learn to love it more.
Hopefully, it will be a good little while before garden variety scammers and spammers figure out how to counter these new tricks.
So you can officially color me an unabashed Blur fanboi. I suggest that true paranoids also use a throwaway destination email address for Blur, just in case.
So definitely try Blur, it is mostly free and works a lot better than DNT, which I previously found a bit buggy and resource hungry.