Another way would be using the search function on the forum, see if it turns up scam accusation threads or you could directly go to the scam accusation section and look through it. Googling would also turn up some.
I went to add the domain I had listed in this thread (won't list it again as some one accused me of trying to promote it) to the thread you listed but it appears that doublers are already so common to be a scam that they don't want them added. I guess this just helps to show how little I do know still about cryptocurrency in general, but I am learning.
At least you have some idea now about that thing and as time passes, you will enhanced your knowledge in the world of cryptocurrency. By maximizing your common sense you will sense or automatically known if a site is a shit one and will never gave you a good output in terms of long term investment.
Like I said, work to earn rather than relying on those shit site with shit returns promised. There are lots of opportunities to earn bitcoin if we think outside the box or should I say, much better if you will remove the box.
I strongly agree, we need to give efforst before we earn and those what so called shit site are what so called scam since they offer some unrealistic profits while they cannot give proper documentation about what business they have, and those lazy man arr mostly their victims since they are believing that theirs a site can give them profits for just doing nothing, and believe me all investment site are scam and just point it that way so we will not fall in their bad schemes ahead, we should think advance before its to late.