Well, it's long been established that:
1) MOST people show up, read, and move on (it's like they were never here);
2) A LOT of people never bother to register for a board, which (I believe) makes it harder to post (at least on some boards);
3) A FEW people are turned off by some of the sex/violence/misogyny/etc., and it's probably better they do NOT post a response;
Then there's people like ME. I read a LOT (!!) of the stories here and usually don't post a reply. Sometimes there's a reason why, mostly I'm just too lazy.
I WILL post if I think a story earns a post either to make MY LIFE easier (mis-spellings, poor format, etc) or if I enjoyed it for some reason (interesting set-up, good character development, etc) although a lot of the stories on here would get a reply IMHO for those (maybe too many for me to bother?)
If a story does something out of the "ordinary" I often post (good or bad) just to remark on it being an "outlier" of sorts. Like a boxing or MMA story when most are catfight/sexfight.
Then there's the "space" issue. If everyone who read a story posted a "well done. Thanks" it would soon run to a hundred replies per story. The board would take forever to get thru (and most wouldn't even read those replies once they got to the end of the story).
Sadly, I've given up expecting (or even wanting) replies to the stories I posted - although I don't do much posting any more. But then I think wanting to get a response is NOT what a writer should be aiming for (unless he's doing it for a living, then it's mandatory!) If you enjoy writing, write. If not, don't. But it should never be about the praise and adulation from the public. That's fools gold, my friend.
Please keep writing and posting if you enjoy it. "It's the journey, not the destination that's important." (I think someone famous said that or something like it)