Well, it looks like the Effies are following in the footsteps of industry advertising ads like CP&B's ads for Young Guns submissions and that quasi-controversial ad promoting Advertising Week which used sex or innuendo.
Read on to see the banner ad for the 2006 Effies. It was found on Adage.com promoting their new categories for awards.
What a nude model has to do with effectiveness in advertising I'm not sure. Maybe they are trying to bring home the point that sex sells. ;)