Fired Fast Company Web chief admits he was moonlightingHere's a career tip from Ed Sussman, the fired head of Mansueto Digital: Have a startup in your back pocket. Since March, he reveals, he's been working on a side project while running the websites of Fast Company and Inc. magazines for Mansueto Ventures. His job was one of 20 eliminated in the cutbacks, which primarily hit the company's online and events divisions. He tells Mediabistro that he and his partners have "put some 4,000 hours into the project" — an effort to commercialize Drupal, an open-source blog software program. Gosh, do you think his boss would have waited until October to lay off Sussman if he had known how much free time his employee had on his hands?