I opened one for shit and giggles,in 2015 I logged in
and was surprised to see the site was alive
withdrew around 48$
so yeah,there was a profitable mining site for me
Not really sure that's a mining site? It sounds like you're describing a ponzi scheme.
A ponzi scheme is arguably one fo the best ways to win and lose Bitcoin (get in the right placce at the right time and you may et your money back, otherwise, it's gone)!.
think they closed by now but they were still in business in 2015
a rare ponzi would survive 2 years of operation without collapsing
if I find their name in my browser cache or history I'll post it here