Kuvian, the one thing I'd caution about is using his population figures. We don't truly know what that population value is, because there is no reliable way to determine how many people are on the server (with the 'anon' tag). Someone can take a guestimate, but that's all it is. Otherwise, everything else players tend to watch for each new month's update.
TL;DR: What Crys said. It's just a researched opinion/guess/assumption. Everything I show on counting highs and meds are accurate, personally recorded, etc. The graphs, if you click the link to Imgur, shows how I actually reached the hours. When you see a black box, that means the server was down. When you see a grey box, it means, I either was sleeping, too busy to log it, or a couple months ago there was a period of like 2-3 days where the SOE Status page was not working. Fortunately, beginning with this month, I now have access to all hours, including when I sleep. Most importantly, as Crys already said, don't take my Low = 500 stat as anymore than a researched assumption/guess. As I put in the FAQ part of the end of my post. I truly do believe the server goes Medium status at 500 or 501. This is based off a few things like using a round number (as opposed to it being say 538 or something weird) but mostly it was from spending nearly an entire month consistently logging in all the servers RIGHT before I knew it would hit Medium and then check the populations right after it did. After many, many days of checking many hours, most of the servers, I never once could find a "Low" server that had over 500 people on it. Unfortunately that method isn't going to work for me to determine the number that the servers goes from Med to High because when the server is busy, people are spread out all over. I would need a high level porter or something and have to spend 30mins checking like all the zones that are actually populated and then start check THAT trend. But geez, that's a lot more involved for something that even after the work is done, people can (and will) easily point out "you're still uh....making assumptions here!" Which is true. Take the 500 number as nothing more than my best guess based off trends and personally logging into a bunch of servers and /who count the major hub zones.
I think Crys, that the /who count command does count anon people, nor does it get truncated. I just unfortunately don't have a /who all count command ever since it was disabled.
