axis labels are hard to parse
During my last presentation for school students, I noticed that reading the y-labels on graphs such as the "Direct users by country" one at https://metrics.torproject.org/userstats-relay-country.html is unnecessarily difficult and error prone. It always ends up being a game of count-the-zeroes, and people are notoriously bad at counting items in a list of identical things.
Maybe instead of 15000000 we could either write "1,500,000" or "1 500 000" (smaller spaces if available) or even 1.5e6. All of them would be preferable (second one is my favorite).