http://ttevhjjsjxz6uqqcjkbig5cycd7n7xv7cmd6f5fcvrqaaa7f3bj36wad.onion/technology/security/pow/index.html
They are also sold for use in other ways in the
criminal underground, which are more popular than Monero mining, because: High CPU usage from a compromised machine sets off alarm bells to people --
when your fans start blasting on a laptop non-stop, or your phone gets red-hot
and your battery life plummets, you know something is wrong, and investigate,
or reinstall. This is different for compromised machines that just blast
network activity.