1. The number of hits on your story measures just the number of hits. That's the number of times your story was clicked on. (Depending on the counter, it may be the number of unique IP numbers that clicked. Still don't know what the AO3 uses.) That number is going to be several times higher than the number of actual human beings who start reading your story (never mind the number who finish it, etc., for which
see TFV's post).
I typically click on a story multiple times. I open it in a new window. I usually don't find time to read it right then, so I'll bookmark it for later. Often I'll open it up at a later time--sometimes from a different location, because I have a laptop--and then find that I STILL don't have time to read it. Lather, rinse, repeat.
I also click on a story several more times if I'm reccing it, so as to make sure my link is correct, that I've got all the author/story info right, etc.
In other words, the more I like a story, the more I drive up its hit count!
What I'm saying, basically, is that hit counters are worthless. :)
Also, anecdotally--and I've told this story before--I posted a fairly popular story a few years ago, and guessing that it would probably be popular (some themes just
are), I decided to take the opportunity to use it experimentally, and so I put a hit counter on it. Today, that story has 52,303 hits. Total number of comments, divided by two to exclude my replies to comments: 342. That's a ratio of 153 hits:1 comment, for whatever it's worth ... which, as we've just discovered, is nothing.
2. Personally, I really don't care how or in what way you comment on my stories, posts, etc. ... I mean, I have received some TRULY bizarre comments, but when that happens, I just raise an eyebrow and move on and forget about it. So if you're wondering if you should comment on something I've posted, the answer is yes, and don't worry about it. Worst case scenario, I go "wtf" in my head and then forget about it by the next day. (Exceptions obviously apply for spam and shit that's just plain Wrong.)
Also, for the record, "I don't like this sort of thing but I did like your story" is a totally welcome type of comment here. I love those. Bring 'em on.
ETA: Also, I'm really lazy, and I understand laziness, so if you don't comment on a story at all, I will not hold it against you. But definitely feel free to make noise at me anytime, if that's what you want to do.