This really depends on what you call profitable. I wrote most of these stories for myself or as commissions, so there were no real costs for me. The online sales turn up a couple of hundred dollars a month, which is fine (although I still have to pay taxes on them). So it's not as if I am making any real cash, but it's a bonus and it's incredibly motivating to see that other people are into the same shit as you.
I would recommend you do it!
I would recommend you do it!