Out of an audience that you might expect to be just about the most captive audience you could imagine, only 30% are flocking to Sony's PlayStation Vita handheld. That audience is the world of PS3 owners. And not just any PS3 owners, but some of the most ardent PlayStation fans on the market. It isn't great news for Sony, but there is still much room to grow. Will it be able to, though? That's the question.