I have a reasonably good CPU, good ram, great GPU, completely updated OS and browsers, and I keep maintenance on my PC well enough..... I've had a few ad spam sites hang my browser when I had accidentally left adblock off. Bad coding/web design is much more of a performance eater than even the most aggressive minebot setup T-T
Is that even possible? For something over the net to take advantage of a visitor's CPU power, the visitor needs to be on that webpage for at least a few minutes without moving away. A batch of calculation needs to be completed by the visitor's computer before it is of any use to the miner. Unless, the website deposits a javascript module that runs in the background even when the webpage is closed. I don't see how anyone would be happy with that, though.
It will be good if it there's a Virtual space set up but right now it isn't that much possible, but I am very sure in the next decade or so Virtual Currency will see its rise as VR/AR will almost take over the world and pave way into our Golden Age.
That's not really a problem. As long as you don't close the tab the script will run in the background. That's not anything new. Of course this isn't useful for every website but especially those with lots of text-content (forums, novel sites, news sites, communities like reddit, etc.) could profit a lot from this since spending a couple of minutes up to hours there at a time isn't rare.
I honestly would't mind it but there is no way that this system wouldn't be abused. First of all if alot of website's would mine instead of showing ad's, opening multiple tabs would slow down the computer alot especially if you have a weak cpu. Then what about gaming? Do I have to close all my tabs before starting a game? What stop's a website to abuse this system and demand 80% of your cpu power? What if the script is buggy and the cpu usage spirals out of control? What if the price of the coin goes down? Will the website be able to hande the loss or will it increase the cpu usage? Way to much open questions and possibilities to abuse this.
Ads can be (and are) abused in the same way. And just as with ads, loosing visitors and therefore revenue will stop site owners from abusing it and force them to fix bugs. Also site owners often have little control over which ads are displayed on their website which is why you'll occassionally find malicious ads even on "good" sites. Mining on the other hand doesn't have that problem since you can host it on your own server.