Parents need to know that this MMOG (massive multiplayer online game), in beta, was very addictive. In fact, it has 150 million fans in Korea. For these short races there are no real rules of the road, so kids won't learn responsible driving by playing. Players are also subject to the occasional rude and inappropriate play and comments of others they race against, which is why Common Sense Media only recommends online games for kids 12 and up. Watch out for extra costs: The game makes money by having its players upgrade cars and characters. A new virtual car can cost up to $10. Outfitting your character with cool gear costs about $2-3 per item.