But... introducing a site that ALLOWS you to see what realms are similar to yours.
I'm going to say many don't know about his other VERY popular, very helpful site called realmpop. A ingenious site that counts populations in a way I never thought of before. A quote take from the site states how they come up with the numbers:
How - To get the list of characters for a realm, first we record all the characters who posted to the auction house. Then we fetch and record their guild rosters. This should cover the majority of characters on a realm. To avoid getting listed, a character must never post to the auction house, and never belong to a guild where a guild member posts to the auction house.
What is lacking in graphic beauty on these set of sights is made up for in totality by the sheer amount of info provided.
Thank you Erorus for adding so much to the WOW community and thanks to WOW Insider for doing this interview.