It's possible for people who knows how to make big money with bitcoins, experience is very important here, newbies can't do it at my opinion.
Newbies can do it too. If they know anything about a service that's being asked for at Services, they can earn money easily.
Yes I still considered myself a newbie since I was still like 6 months with bitcoin thing. And I am still not good into finding a legit investment site. Still do not have some good friends to trade some bitcoins. But I am happy on what I am earning right now. It is just a matter of reading and reading and learning.