A new site came up recently Realm Pop That showcases actual realm populations for warcraft servers in EU/US thanks to the open API blizzard recently released. It gives an accurate indication of how many characters are on a particular realm, how many are 85, what races, classes and factions there. You can even click on the realm for more detail on the largest guilds and exact faction breakdowns. There have been other WoW statistics websites over the years but all of them required an addon by the client to gauge an estimate of the particular realm population. This uses purely API scanner that looks at every single armory page on battle.net and gives an exact total.