Gameloft hasn't yet dipped its toes into ad-funded mobile games, but one of its executives is, after leaving the company to join US firm Cellufun.

Keith Katz was head of North American marketing for Gameloft, but is now taking up a role as VP of marketing at Cellufun, which runs its own mobile games portal offering free games to users.

Katz has also worked at Atari and the NFL in the past, and will hope to bring his branding experience to bear in his new role at Cellufun. "As someone with a background in both console and mobile video games, I see Cellufun at the epicenter of both worlds," he says.

"Cellufun's offerings have the 'stickiness' and community feel of an MMO like World of Warcraft or Second Life that avid gamers crave, but they also possess the 'pick up and playability' that many casual web and mobile game players prefer."

Meanwhile, Cellufun has appointed Tom Burgess to its advisory board. Burgess is currently entrepreneur-in-residence at Battery Ventures, but was previously founder and CEO of Third Screen Media, the mobile advertising agency that was bought by AOL last year.

He'll be focusing on developing new mobile gaming advertising models for the company going forward.