My Credit Card Number Is...

Call me old-fashioned, but I have a hard time giving my credit card number and purchase pattern information to every Tom, Dick, or Harry who asks for it. I'm even less thrilled about having that information broadcast to all of my beloved friends and followers online.
In the last year, services like Blippy, which connect directly to your credit card transactions and post them onto your social networks for the world to see, have become popular ways of sharing personal information within social networks. It makes me cringe. Status symbol or not, I don't feel comfortable sharing that information or linking my credit card account so publicly. (I still black out my purchasing information when I use my bills as receipts.) If I feel the world needs to know that I spent $150 on a pair of jeans, I'll post that information myself, thank-you very much.
A couple of days ago, TechCrunch reported on a soon-to-launch service called Offermatic, which asks users to give up their credit card information and transactions in return for savings based on recent purchases. For example, if you recently purchased a kitchen table, you might get an offer for $10 off kitchenware at Ikea. I'm all for saving money, and actually LOVE the daily Groupon offers that I get. I also agree that this is definitely an interesting and highly targeted idea, ideal for advertisers looking to push their product or service, but I still don't feel comfortable allowing a third party to sort through and analyze my credit transactions (anonymously or not). Personally, I can't see myself signing up for Offermatic or Blippy anytime soon. I can't shake the paranoia that some other analysis of my data may be taking place in the back end, behind the scenes.
What do you think? Too Big-Brothery for you? Or are you more from the camp of "meh, what's the worst that could happen?"