Its wonderful that you've earned some money from those freelancing marketplace sites. I'm active on one freelancing site, which is freelancing.com. it seems my best pick at the moment, when it comes to freelancing work.I have made money from upwork, seoclreks, and iwriter. On upwork and seoclerks I did different kinds of work, not just writing, however, on iwriter, I wrote for clients. I have never worked on article marketplace.