I found a twitter account by the name of Marlton Johnson. He's talking about Nuketown. I think he could lead us to the next step. Maybe he's made by Treyarch to give hints about the easter eggs! His Twitter is: @MarltonJohnson
Call of Duty Zombies (CODZ) is a fan-managed gaming community centered around the popular Call of Duty franchise with central focus on the Zombies mode. Created in 2009, CoDZ is the ultimate platform for discussing Zombies theories, strategies, and connecting players.