You're familiar with the Entertainment Software Ratings Board (ESRB), right? They're the lot who help moms and dads ensure that their kiddies only get their grubby mitts on age-appropriate content. Recently, the ESRB's reach extended into the mobile space, but it turns out that Apple and Google aren't down with the ESRB's handy dandy ratings system. Despite being invited to the party, the two tech behemoths with matching app purchasing portals are quite content with their existing controls, thank you very much. Of course, the fact that the ESRB relies on developers to complete a detailed questionnaire instead of reviewing every app itself (not unlike existing Android Market and App Store protocols) might have something to do with Cupertino and Mountain View's reluctance to jump on the bandwagon. Looks like parents wanting to keep their kid's devices free from inappropriate content will have to remain vigilant without the ESRB's help.