One of the latest developments in cybersecurity is the advent of microstealing. Criminals are planting software that uses your computer hardware to accomplish tasks.
The criminals may add software to a site, so when you read the news, a script runs in the background that mines cryptocurrency. The criminals earn a little money from each person who visits the site.
It does affect the person who they use the computing power from, since the computer uses more electricity and may perform other operations slower than normal.
This is not necessarily a new development. For many years spammers have been installing software to send out spam on people's computers.
The interesting development is that this software runs from a web site and when you leave the site it stops. Spamming software was often discovered, because the computer would noticeably slow down.
The new development is that with the advent of cryptocurrency it is possible to monetize lots of small slices of computing time. It does not generate large amounts of money since serious mining is now being done on specialized computers that are optimized for this type of computing. The difficulty of mining and therefore profit from mining is dependent on the amount of processing available. As there is more processing available it requires more work to earn currency.
As you browse the web pay attention to your computer. If you notice it being sluggish, you may be mining bitcoin. Usually closing the browser will stop the script, however sometimes they will pop up a tiny window and hope you don't notice it.
This is one more thing to watch out for as you browse the web.