New submissions can't be downvoted, so for those I can only learn from which ones (mine or other people's) get the most upvotes. I think I have noticed there's

New submissions can't be downvoted, so for those I can only learn from which ones (mine or other people's) get the most upvotes. I think I have noticed there's a huge time-sensitivity on which stories "catch on". In other words, I suspect you could post the same link twelve hours apart and get a completely different number of upvotes. I speculate that this is because readership is concentrated in the PST timezone. So story lack-of-upvoting isn't quite the same learning experience as comment-downvoting.