I can't help but think this is a conscious decision by Nintendo.  The sheer bravado as they go into this console life cycle without as little as a whisper of Wii U trickling out of their gullets towards casual crowds. 

To them I say, fool hardy.  Fool hardy, and God Dammit Brave! 

That's why Nintendo is Nintendo.  They make unpopular choices, follow through, and make bagazillion of dollars.  I'm glad to see a games company who has balls a are a little nutty.  Pun intended.

I think its a little too early for ads. I mean, picture yourself as joe schmoe casual. You're sitting there, thinking about halloween, drinking a beer, and this ad comes on for the latest and greatest new home console. Now Joe just has to have every new gadget as soon as he can, so he says "Hot diggity dawg. I'm gunna get myself that thar WiiU kajigger!" (Yes, Joe is from Georgia, possibly Alabama).

So he gets in his truck and drives to the store only to find that nobody there has any idea what he's talking about (and not just because of his accent). Joe goes home, watches more football, and every time he sees a commercial he goes "That there thing is a lie. I dun been to walmart and they don't have em!"

So Nintendo wastes oodles of dollars on advertising when they don't even have a product to deliver yet. Bad idea. Wait until the week before or the week of. The retailers will be fully briefed on the product, and may even have the product in their warehouses waiting for the OK to sell. Joe comes in a week before and they tell him "We'll have them next week, but you can go ahead and put money down on some games." Joe spends money, and his anticipation grows instead of being pissed off.

Only in this case, he'll be more pissed off because his local wally world is completely sold out and won't get another shipment until mid December. His kids, Joe Jr and Sally Schmoe, are now bugging him to get one for Christmas. Plus he's already reserved some games. So he goes to ebay to buy an aftermarket one, plunks down 500-1000 dollars, and I make a hefty profit.

And they all lived happily ever after, The End.

Judging by how some retailers have stoopped taking preorders, they probably have sold out on what they can offer first shipment.

What is the point advertising the WiiU only to piss people off with "SOLD OUT" signs in stores. The ads will come ones the console ha sa steady stream on shelves.

As a poster above said: Brand Awareness.  The consoles may be sold out, but the games won't be, and they'll need to advertise the games, and thus the consoles as well.

Apple also never advertises a new iteration that is not immediately available for purchase. They usually don't even announce a product until just before it launches.

Since demand is so strong already and supplies are running low they might as well wait with the advertisements until November.

I think Nintendo has chosen to advertise by having potential consumers get their hands on the Wii U at certain events like the 'Wii U Experience' tours in places like Chicago and L.A. I'm sure they have done, or will be doing, similar marketing events in other countries as well.