With the anniversary bundle and holiday boost, it should make 20 million before January.

It'll hit 20 million with no problems.

I don't believe it can beat Wii Fit, but there is a good chance for second place.

Update

Black Friday week sales are in and there are 54 weeks of sales reported. There are 6 weeks of sales left with 2.4m units left to go. Or 400k/week. With the new bundle and last weeks sales of 600k it is looking more likely that NSMBWii takes over the crown.

600k for NSMBWii! That's amazing after being released over a year ago. I don't think anyone can deny that Nintendo is THE BEST video game developer/publisher in the world, they've got some sort of magic touch when it comes to this stuff

NSMBWii will become the fastest selling game to 20m no doubt, it's at 17.60m right now after 54 weeks of data and selling over 600k last week

It didn't do it quite as quickly as I would've imagined, though good job anyway. Let's see if it can do the same with 25m -- Wii Fit couldn't make it 'cause of WFP so it shouldn't be such a close call, especially if it stays bundled for a while.

Im sorry but given the fact that everything is multiplatform I don't believe a game gets a free pass because the maker decided to release it on the one platform. It may be the fastest selling exclusive title to one platform but it will never be the fastest selling game. Exclusive content as a whole is a thing of the past, heck even browser games are no longer really exclusive to PCs.

Actually, Nintendo didn't just release it on one platform. They released it on DS as well. I don't know why on Earth we just compare its individual sales, :P. Let's see how fast NSMB did it launch aligned.

Sure, go ahead.

That would be a more fun comparison actually, xD.