Also It’s a bit overdue, but coming with the next system update in late November is the ability for Nintendo and third parties to release demos of their games via the eShop. In line with this, it was also confirmed that we’ll be able to download things from the eShop and put our 3DS to sleep without interrupting the download.
Finally Satoru Iwata has confirmed that, once the next system update hits in late November, it will be possible for developers to provide downloadable content for their games. This is somewhat possible at the moment, with games like Dead or Alive: Dimensions providing bonus costumes and Samurai Warriors: Chronicle providing bonus scenarios, but I imagine the functionality will be expanded to support larger sorts of content. This is “a feature a number of software creators have been looking forward to,” so hopefully they make use of it.