There is something that I haven't seen anyone here (staff or forum) mention yet and that is the notepad and other multi-tasking features.
http://kotaku.com/5738668/short-cords-long-friend-lists-and-other-burning-3ds-questions-answeredThe 3DS seems like a pretty capable machine. One of its less ballyhooed features is that you can multi-task with it. How does that work?
A 3DS owner user can suspend any game they are playing at any point and access one of several options (all displayed across the top of the screen) that let them access a virtual notepad, a web browser and even a friends list that lets them see who else is online. As for how useful this might be: "Specifically for an example with Zelda," Nintendo's Trinen says, "If you're stuck in the water temple and you're trying to figure out where the last of the switches are that you have to hit to draw the water level down and get all the way down to the boss, you can immediately hit the home button, bring up the browser, go to whatever tip site you want to go to, figure out where that is, then switch over to the game notes, draw a map on your screen to refer to or go right back into the game." All of this can be done with the game suspended, which is superior level of support for multi-tasking than any game machine has ever offered before.
video:
http://www.youtube.com/watch?v=IrI7uTMjGic&feature=player_embedded notepad starts at 18:20
Note pad sounds like a great addition that no one was asking for but Nintendo brought to us anyway. being able to take notes during the game and access them at any time, not to mention being able to exit out and go browse GameFaqs for some quick help should you need it, will become invaluable to lots of gamers.
I don't know all the details on the feature, but the only other thing I could really ask from the notepad feature at this point is the ability to snap a photo of a game screen and then use that to draw on. Imagine playing a FPS or RPG and you bring up the map screen and you want to remember where a certain item/object/person is or an exit but there is no option to mark that stuff in-game, so you suspend state the game, take a screen capture of what was on the bottom screen and the map now fills your notepad. Now you are free to mark it up in anyway you want and save it to your SD card.
The other thing that hasn't been talked about is the lack of Picto Chat on the 3DS. It may or may be attached to the friends list, but since we don't know anything about the friends list, I guess we wouldn't really know. But the all knowing Nintendo rep from the video says he hasn't seen or heard anything about a Picto Chat for 3DS so I guess we can assume that it was left out even though Nintendo has mentioned some sort of messaging.
We know the Friend Code system is better this time around. Can you even send messages to people while you're playing, maybe while the game is suspended?
Trinen says "the goal is there will be some messaging functions" but couldn't lock in details for us.
Picto Chat may not have been a heavily used feature on the DS/i, but that's mostly because I have to be next to whoever I was picto chatting with and so that just leaves me and whoever else is in my house with a DS.... not very useful. With the multi-tasking of the 3DS and being able to get different notifications and suspend state games, an online friendlist enabled picto-chat could be Nintendo's Instant Messenger. You should be able to send pics to and message your friends that happen to be online regardless of what they are doing on their 3DS. Actually, any messages you send should notify them the minute they connect online regardless of when you sent it. I would be really disappointed to not see a new and improved version of Picto Chat to accompany the 3DS and use all of it's features. I guarantee it would get used by more 3DS users more often the the novelty that was the original on the DS.
other things talked about in the video are Mii Creation and Face Morphing. But can somebody please explain the differences between Street Pass & Spot Pass?
edit: Speaking of Mii creation, lets hope that Nintendo is more forward thinking this time around about how Mii are inserted into the games and how games should interact with the OS regardless of what version it is and therefore new features to the system won't break a games compatibility. This way if Nintendo releases a Wii2 and it has an even more advanced Mii creation set, Nintendo can go back and update the 3DS Mii creation set and the 2 can be equal and all previously released 3DS games will also be able to use those new assets and everyone is happy.