The event was aimed primarily at Gold and Platinum Club Nintendo Members, and a few details on Nintendo's third DS iteration have been re-confirmed; 0, 500, or 800 Nintendo Point costs for games and applications; A soft reset function on the DSi by a quick tap of the power button; the Opera Internet Browser (thankfully of better quality than the previous one) not being built in, but available in the store from day one; and a free 1000 points to spend when you first hook up to the service.
The big reveal here though, and most likely the reason you clicked on this story, is that original Game Boy games and Game Boy Advance titles will be up to purchase and download very soon. Much like the Wii's Virtual Console service, there will mainly be just first-party Nintendo titles up for grabs at first, and like the DSi shop in general, will all be region locked.
One thing that will greatly please frequent fridge-cleaners is that gamers will be able to save and run these games directly from an SD Card in the DSi System, hopefully a sign of things to come for Wii. 8GB cards have been confirmed to work with the unit, so there should be no trouble with storage space.
Suddenly, Nintendo's decision to remove the GBA slot makes a little more sense. Those sneaky buggers, eh?