Can DECODE "up to 4 simultaneous video stream".

I do think that the GPU will also have to compress the output (that will be displayed to the remote) with some sort of high compression, low latency codec. That would be the issue.
One can argue that Nintendo could add some sort of specialized video encoder chip but it doesn't fit with the whole"I want to make as much profit as possible and that's why the WiiU will be with the 3DS the sole consumer devices still shipping with a resitive touch screen" scheme.

Resizing the picture not the issue (especially if rendered at the right size), but compressing it with minimal lag while looking loseless and fitting under 15Mbs will need some processing power.
A 30fps uncompressed WVGA stream is around 330Mbs if I'm not mistaken.

For me, it's the "1 controller with display limit" combined with "same quality on TV and on the controller".
Generating graphics on the controller would allow technically breaking the limit, because you would be basically sending OpenGL commands via bluetooth, and that's scalable.

But it would be a fking expensive controller.

Generating two views, compressing one to AVC, sending it via wifi, and the controller side only having a custom asic decoding video with a C sending back button and touch information. Make more industrial sense and is way cheaper.

I also expect that the quality of the main (TV) screen will have to be severely downgraded when the other one is enabled. Considering the HW architecture of the ATI GPU, I think that a not negligible amount of GPU cores are used to trans-code the aux screen output to some kind of compressed video feed.

The point is that usually big N was cheap enough to use standard technologies, without the certifications. In this case, the WiiU would use a standard bluray drive (because they are mass produced by ton of factories and it is mature), but the data file format/layout on the drive would be proprietary. By not bundling video bluray/dvd playing capability, Nintendo doesn't have to pay the better part of patent fees.

As seen on their latest phones and cameras, Sony doesn't use MemoryStick anymore.

Paul Thurrot made a few test a while back:
Firefox (any number of windows/tabs that derives from it) = 1 application.
Any explorer derived window (Internet Explorer included) don't count.
Many built-in apps don't count. (calculator, notepad...)
Daemons (background/taskbar apps) usually don't count.

It seems there is both a white list of "free apps" and a scheme to define if a new process is a part of an existing app.

Some manufacturer leaked that Windows XP cost around $15 per netbook. The point would be that "Windows 7, crippled edition" would be sold very cheap, so manufacturers are happy, and it's still windows, so consumers that want to run Office 2007 are happy.

Another thing to consider is that if you want to ship a netbook with Ubuntu (free) that plays videos/music, you'll (at least in europe) have to licence codecs. At the official store (http://shop.canonical.com/product_info.php?products_id=244) , A/V codec for Ubuntu cost $36, (only audio codec are sold for $26).

Windows XP includes those codecs (except mpeg2/h264)
Windows 7 include them all (including encoding)

So, from a manufacturer point of view, Linux may be as expensive as Windows, with the added fear that consumer will complain because they wan't install their favorite messenger.

And even if it's free, that oddly don't mean that I won't try to buy something from the artist. I think that they are underestimating internet users, I know that artists have to live, they deserve profits for they success. But because we're also cheapskates, paying 20euros (26usd) for an album is definitely too expensive.

I think they don't hate Linux, they just don't care... I /may/ be that the took the code from another motherboard, made some quick & dirty changes to the dsdt table and submited it to the automated WHQL verificator until it succeed. And since this board only support XP or Vista (check the manual), old, out-of-date parts of code are floating in the BIOS. Nobody cares, nobody will react. Engineering something correct is too expensive nowadays, so engineers are only told to make something that works.