I recently had a third-party seller from an Amazon purchase send me a marketing postcard. Item was "fulfilled by Amazon", so transmitting my address to the seller was not needed to fulfill my order.

The postcard contained a call-to-action to visit a URL. Fortunately, I was suspicious and went there in an incognito window, because it redirected to use a signed-in facebook session to send themselves a message, presumably to harvest more data about me.

I wrote a review on the product condemning this practice and Amazon removed the review as "not about the product". Quite frustrating - seems Amazon just doesn't care about customer privacy.