Nintendo has called this their "third pillar", a new product distinct from their GBAs and GCNs. But could it really be the start of a whole new line of products separate from consoles and (Game Boy) handhelds?
Obviously details are still scarce about the DS, but I still don't see enough to consider this an entirely new product. It's still a handheld, and primarily for playing games. It might hit a different market if it did more than play games, like playing videos or running applications but I don't see this kind of thing coming from Nintendo.
By not having the Game Boy name attached to it, and insisting on that difference, sure, that's a sign. Though the average Joe consumer would call any handheld a Game Boy.
The "Game Boy" name itself sells a lot...the product must be radically new enough to distinguish itself apart from the other Game Boys (at least to those other than the average Joe) if they won't even call it a Game Boy. Otherwise, as I joked on other boards, they should call it the Game Boy Advance DuAl Screened System. Note the acronym.
I had more questions than this, but I'm guessing like everyone else, we'd have to wait until at least E3 for further details...*sigh*