Yes you can when using it as a marketing platform for your own business, or when you do affiliate marketing. Just like twitter, facebook, reddit, ... can be major sources of income. You can do this fulltime easily but only if you are skilled in internet marketing. Most people don't have the knowledge to pull it off. If you would you shouldn't be asking this question. It's pretty much free to advertise here, that makes steemit a great platform for doing business.
You could also do bounty hunting: https://steemit.com/earnmoney/@niel96/earn-cryptocurrency-from-home-by-doing-tasks-on-bounty0x