Ever noticed the "corners" in the cumulative distribution curve?

Well, those corners/peaks/edges are visible in the differential curve as well. I find it remarkable that it can be seen at all full hundreds. I just looked at the blitz distribution btw. because that's the only one I have got and I'm interested in.

I think these are those experts who climb onto or narrow beyond a certain step and then "retire" for a while. Or they play solely unrated, only other variations possibly or open new accounts...

So, if you wanna take over a lot of them in terms of the percentiles you just have to climb over the full hundred number plus a bit more - then you get an extra many of them. :D

I was wondering about the same thing today. For reasons I can't explain, it bothers me that these curves are not smooth.

I think your explanation is correct. However, I think it would be less visible if:
- instead of intervals of 25 elo points, every score is counted separately.
- players with a large uncertainty on their elo score are not taken into account (not sure if the case now or not)