Slide and RockYou, the two largest developers of Facebook apps, have long had a serious rivalry over the most frivolous Web software. But the two may be pulling apart. Slide, Max Levchin's SuperPoke machine, signaled yesterday that it's betting on online entertainment, partnering with Hollywood to bring mainstream content to its FunSpace apps. RockYou, meanwhile, seems to be turning into a gamemaker. "We want to be like the Electronic Arts of social networks, and build games for social networks," RockYou CEO Lance Tokuda, shown here, said today at the Startonomics conference in San Francisco, referring to the dominant maker of videogames.Build, or perhaps buy. In July, RockYou acquired Speed Racing, one of the top games on Facebook. But RockYou, in diverting its attention from its rivalry with Slide, will face well-funded competitors in startups Zynga and SGN. By the time all this becomes a serious business, isn't it just as likely Electronic Arts will be the Electronic Arts of social games?