What do you do after writing a book called “The End of Advertising?” If you’re Andrew Essex, you co-found an advertising company. But Plan A, he says, is built on a different model than the traditional holding company. A former journalist and the co-founding CEO of Droga5, Essex brings with him an impressive pedigree. We get into that background, where the industry is going, consultancies, the breakdown of the traditional models and what’s next for Plan A.