I would speak frequently with a manager at the local TRU, and even in the summer people would be lining up outside the store on "Wii Sundays" to get their copies. I can't imagine they were all hardcore gamers (indeed, many at this site would say purchasing a Wii immediately brands them as casuals), so there were clearly many casuals who were aware of the shortage and learned to plan accordingly. Given how many people shop early for XMas (my mother in law probaby already started her 2008 shopping), I don't find this story to stretch credibility.

I would speak frequently with a manager at the local TRU, and even in the summer people would be lining up outside the store on "Wii Sundays" to get their copies. I can't imagine they were all hardcore gamers (indeed, many at this site would say purchasing a Wii immediately brands them as casuals), so there were clearly many casuals who were aware of the shortage and learned to plan accordingly. Given how many people shop early for XMas (my mother in law probaby already started her 2008 shopping), I don't find this story to stretch credibility.

Maybe those parents weren't able to get their kids a Wii last Christmas and they didn't want to disappoint their kids again this Christmas?

The answer for this comes down to three essential things:
- Userbase
- Christmas
- Demographics

The Wii has a larger userbase than the Xbox 360, therefore all else equal you would expect higher sales on the Wii.

The second and third reasons are connected. One would expect that the Wii's audience would be on average younger than that of its competition (due to Nintendo's image, lack of violent games etc) and Christmas presents tend to be directed more towards this demographic than the perhaps older demographics that frequent the Xbox 360. Therefore all else equal you would expect the Wii to get a bigger software  boost at Christmas than the Xbox 360.

Couple the effects together and you get the Wii outselling the 360 significantly over the Christmas period.

@Diomedes1976
>Well I think the Wii is selling more like a toy than anything and in that context its >usual to see toy sales explode in christmas

Hilarious explanation for increased Wii sales :)
Finally all video consoles are nothing but toys (though some time of the year PS3s sold more like bricks than like toys compared to Sony's expectations ....)

 Than read it again ...

I find melissas answer the most plausable to ... I really want to know how the next gen of PS3 games will compare with 360 games :) 

BTW, are the PS3's software sales getting any better? Would those trying to discount the Wii "forget" those excuses if the PS3 was selling more games than they were?

 Well, the Wii has always sold lots of software.  I already bought 12 Wii, 11 Gamecube, and 5 VC games because to play on my Wii.  Maybe people were lying to you?  Maybe you were just looking at American software sales where the Wii is weakest and the 360 is strongest?

I planted bombs in them, that's why.

Perhaps an increase of console sales during the holidays is the reason...