What's my real issue with this? Nintendo does this for absolutely everything.
They wait until the week-of to advertise, they manage PR and attempt to attract celebrities to their products, and they try to manage everything through word-of-mouth, as well. The only thing they didn't do this with was Brawl, IIRC. They did it with Metroid Prime 3 (aside from that lame preview channel, I mean), Mario Party 8, Super Paper Mario, Super Mario Galaxy, and practically everything they've released on the Wii.
This strategy works well for this particular game, like it did for the Wii in general (as well as Mario Party

, but it doesn't work for these other games very well. What sold Super Mario Galaxy? Mario did, not Nintendo's ads. What sold Super Paper Mario? Mario, not ads. Battalion Wars was doomed from the beginning. Mario Strikers sold, but it wasn't thanks to advertising methods.
Why is it that we've been seeing GTA IV commercials all month long? Why is Master Chief plastered everywhere. Nintendo would be better off just saying that they don't need to advertise to sell games, because the fact is, the competition's advertisement strategies are much more comprehensive. Maybe it's just me, or perhaps they don't hit smaller cities, but Nintendo's ads haven't done much in a very long time, from my perception.