I'm pretty sure I remember reading one or more really good stories on SOL by an author named Young Thinker.
I may be doing something wrong in my search terms, but I don't find any such author listed and also see no mention in the list of no-longer-active authors.
I do not recall the titles of any of the stories.
Now using a different name, maybe?
He pulled everything down back in, maybe 2012? Been a long time, that much I know. Big on bother/sister incest and romance.
I just looked in the Wayback Machine (November 2015) and he had 255 stories up at that time, the most recent one was posted in mid June of that year.
Wayback snapshots are at irregular intervals, his index entry was still there on 27 November but had vanished on 4 Jan 2016.
Quoting from his Blog:
Most of my stories involve a, or a few, sister(s) and/or cousins.
I seems to recall that he became engaged to marry and decided to take the stories down. I guess he figured a woman might be concerned if her future husband was planning to fuck the kids.
It could be someone else I was thinking of.
ETA: I got the idea from this thread.
https://storiesonline.net/d/s4/t548/whatever-happened-to-young-thinker#po8001