Every kind of business and investment has scam, you must do is to make some analysis or study if those investments are legit or scam. Don't amazed or hooked on those project that will return your capital in a short period of time or gain profit much higher compare to others.
Thats what people are get hooked by, exactly: they look for big profits in short time and scammers use their impatience and greed against them. We should increase our vigilance.