i have not installed any addons but i am running their website from a long time..
What do you mean by "running"? You are the one who runs the website or just an ordinary user of the site?
By the way, I've checked it on scam adviser and the result is
Quote
Low Trust Rating. This Site May Not Be Safe to Use.
http://www.scamadviser.com/check-website/bitminer.ioI think he means on "running" is "even you logout on that site your address will continue to mine.
personally I to have almost 50 wallet address simultaneously mining on that site (using just 1 IP address) before finding out its reputation.
at first I was in doubt because the way it gives satoshis (2 satoshis every second) is too good to be true but I give it a go anyways (what a dumb idea)
but after I found out about tons of negative comments I stop visiting that site. well I haven't tried to withdraw yet because I haven't reach 0.005btc but if it reach I think I'll give it a try just for the sake of "to see is to believe" LOL