they look on the steem blockchain and see the time stamp, then look on the price feeds that come into the steem blockchain (this determines that $ number you see near each post), and then put 2 and 2 together and figure out how much we got paid.
then go in the #introduceyourself category and get photo verification.
they don't even need to store the data in an NSA data center, it's all there on the blockchain.
blockchains are double edged sword sometimes.