This website reminds me of some of my winning jackpots and web browsing mining. I don't know why this website closed the web mining but I still miss that feature and I wish and the developer brings it back.
Web mining thing was removed long time ago. If I'm not mistaken, main reason of removal is antivirus programs - they don't like CPU mining and give warnings to users about it. I think that one of antivurus programs even blocked acces to Freebitco.in. So, it's not very likely that they're going to bring web mining back.
I can remember the Web Mining on freebitcoin too, but it was like 2 weeks no longer, and then they removed it from the page or am I wrong?