Apple had it's turn with mandatory content ratings with iPhone OS 3.0 - but now it's Google's turn. They've announced that the content ratings will become obligatory for all Android developers in a few weeks.
Google also said that they'll be showing ratings for all apps along with other "Android Market upgrades in the coming weeks" - this might fall into the schedule with Gingerbread too.
Any developer that fails to specify a rating level for their existing apps automatically gets dumped in the "Mature" pile until they rectify the rating. In addition to Mature, available ratings to choose from will be Pre-teen, Teen and then "All" which is guaranteed to not offend people like Justin Bieber and JoBros (whom our own Shane Baxtor is a big fan of).
This is good news for parents of Android owners, or family members/friends who allow children to use their phone for games - and just in time for the holiday season.
It's also good news as it seems like Google is evolving their Market, in this tech game - you can't stand still for too long.