I think some of you noticed the Home-button on the 3DS, below the touch screen between start and select. This confirms that there will be a 3DS Home-Menu.
What is the Home-Menu? (For people who don't own a Wii)
The Home-Menu is an in-game menu. When the Menu is opened, the game is paused until the Home-menu is closed. The Home-Menu can be opened at any time, except when you're playing online or when the game is saving. Inside the Home-Menu are a few options.
The Home-Menu of the 3DS will probably be similar to the Wii's Home-Menu. The Wii's Home-Menu allows you to restart the game you're currently playing or to go back to the Wii-menu. These functions will probably also be in the 3DS' Home-Menu, but are there any other things you would want to have in the Home-Menu? Things like an operations guide for the game you're playing etc. (this was already available for VC games, but not for WiiWare and retail games on Wii) Since the online abilities will become greater on 3DS, wouldn't it be nice to see who is playing which game while you take a break and are in the Home-Menu? Or to view the status of the 3DS or general things (battery life left and time & date)? Discuss!
Remember: Once the handheld is out, the Home-Menu can't be easily changed. So, Nintendo must decide which functions the Home-Menu will have before the 3DS is released.

