Distributed computing is an excellent idea. We have a huge network of computers, many of them always on, why not take advantage of that when the user isn’t? The application that probably comes to mind is Folding@home, which lets you donate your unused computer time to help crunch the numbers for disease research. Everyone wins!
But what if your CPU cycles are being used for profit without your knowledge? Over the weekend this turned out to be the case with Showtime on-demand sites which mined Monero coins while the users was pacified by video playback. The video is a sweet treat while the cost of your electric bill is nudged up ever so slightly.