Microsoft is bringing out an old staple and going on the offense that the Wii is nothing but a kiddie system. In the New York Times today John Rodman, group product manager for the Xbox platform and Xbox Live, said, "We don't feel like the Wii customer and the Xbox customer are the same thing ... We think that as soon as the Wii customer turns 14 they want something else."
Shane Kim of Microsoft praised Nintendo, but also stayed on message, in a recent Gamasutra interview, "I don't view Nintendo as a direct competitor, simply because they're not trying to do the same things as we are on the higher end - they don't have the same online aspirations as we do - but Sony and Microsoft really need to compete for that customer segment if we want to get to the mass market and win this generation."
So, although Xbox and PlayStation are for the adults and Wii-Tang Clan is all about the children, Microsoft does realize they need to break into the kiddie demographic. If you're looking for the good spin on this, it's not that Wii isn't for adults as much as Xbox wants to be for the kids.