The news story that you probably heard was that the CBS and Showtime websites were set up so that when you browsed their sites, your browser ran a script that 'mined' a crypto-currency. It turns out that, in this particular case, the code to do this was not authorized by CBS and that some programmer did this in the dark for their own Superman III/Office Space style scam.
What you did not hear was that the mechanism that this back office Richmond used to do all of this is actually legitimate. Just not approved by CBS. And it can help monetize web content AND minimize advertising. How does all of this work? Read on.