We are only familiar with companies who sell using social media. One of our mentors makes over $300,000 a month but he has a staff of 12 working for him. His staff are all experts in their fields. Our apologies, he won't tell us how much his article writer is earning. Our guess is about $8000 a month. We know he only hires the best so it may be more. It requires an unparallelled reputation to earn this kind of money as a writer.
We have heard of a few bloggers who are earning more though. They are writing for themselves and earning for the most part off back end sales through an auto responder. Like in any business it is about location, location, location. The bloggers who fill highly searched niches with low competition keywords of course are going to do best. Social media specialists though especially those who own their own companies are doing much better.