Nobody cared about what's on the postcard because you couldn't easily scan every postcard sent and mine its contents. The average social media post has even les

Nobody cared about what's on the postcard because you couldn't easily scan every postcard sent and mine its contents. The average social media post has even less content (especially sensitive content) than a postcard, but the ease of collection and analysis means that if there is smallest iota of useful information on the card, it can be mined and exploited.