It's an ok article, though technically inaccurate on a few fronts: The difficulty of mining is related to the number of coins mined (not the number of miners).

It's an ok article, though technically inaccurate on a few fronts: The difficulty of mining is related to the number of coins mined (not the number of miners). The miners aren't the "central repo" of the ledger (it's distributed and anyone can download it). shrug