It would appear that the ads are cookie based. I get all kinds for various sites I've visited recently.
Edit: I'm an idiot who didn't see Robb's post.
Total Coasters: 152
Top 10 Steel: Maverick, Intimidator 305, Skyrush, Fury 325, Banshee, Millennium Force, Raptor, Superman: The Ride (SFNE), Top Thrill Dragster, Big Bad Wolf
Top 10 Wood: The Beast, El Toro, Phoenix (Knoebels), Boulder Dash, Thunderbolt (KW), Mystic Timbers, Twister (Knoebels), Hercules, Shivering Timbers, Jack Rabbit (KW)
Top 5 Hybrid: Steel Vengeance, Twisted Timbers, Goliath (SFGAm), Wicked Cyclone, Great White