I just had to create an account and reply to this guy after coming across this thread because he apparently doesn't understand the numbers he's posting about, nor do a lot of people here. These numbers are not the overall population, it is ONLY showing the amount of people that are currently in a game of matchmaking. It's not like h3 or reach. It doesn't include all the people playing spartan ops, campaign, customs, people just sitting in the lobby, etc.
I don't know what is so hard for people to understand about this. And that halo charts website shows the exact same thing(only overall playlist numbers). A little math goes a long way in understanding this stuff.
Go look at halo charts daily peak population chart and the peak is like 450k which was the day after release. Do you REALLY think there was only 450k online on h4 that day? Taking into account the fact that h4 sold 3.1 million copies on day one. Really? That 450k was just the amount of people currently in war games.