each reader (user) has the ability to clap each article 50 times. Which seams like a lot.
At first this system might seem a tad odd, but they did say that the funds for each subscription are handed out to writers based on the distrubution of that individual users claps. so if that individual user is clapping consistently, then it isn't an issue. The only problem I could forsee is good articles getting drowned out because most that read it only clapped once, whereas other articles fewer readers could clap 50x and thus resulting in more claps.
Now that I think of it they don't really say how claps affect visibility.