Miiverse

Miiverse is the Wii U and Nintendo 3DS's social network, integrated into software such as WaraWara Plaza (bustling plaza) to bring people together, communicate, and comment on certain games and software. The network is built similarly to Twitter, as players can "Yeah" (like) and flag comments, as well as follow or befriend other users. Originally only available on Wii U, Miiverse was later released on the Nintendo 3DS as part of a major system update in December 2013. Miiverse is also available to use on smartphones, PCs and tablets allowing the player to answer questions and receive tips even when away from home. It is currently accessible on Wii U, the Nintendo 3DS family of systems, and on Nintendo's website.

New Super Mario Bros. U
New Super Mario Bros. U is the first main Mario title to incorporate Miiverse. Miiverse in New Super Mario Bros. U is used to create comments on specific courses that either inform, advise, or comment on the course itself. Players are also able to use Miiverse to create snapshots/replays of their accomplishments or results of Challenge Mode or Boost Rush Mode and post it on community forums.

Nintendo Land
Miiverse in Nintendo Land works similarly to Miiverse in New Super Mario Bros. U, with the ability to take snapshots of the results of attractions and post comments on the plaza to inform, advise, or communicate with other players.

Game & Wario
A minigame similar to the Sketch minigame in Game & Wario can be played with other users on Miiverse in a mode called Miiverse Sketch.

Super Mario 3D World
In addition to being able to post to Miiverse while playing Super Mario 3D World, players can also collect Stamps in the game, which can be used to customize posts with images of characters and items that are found in the game.

Mario Kart 8
In Mario Kart 8, players will be able to share replay videos of an entire race or a thirty second video created by the software showing the highlights of the race. Players will also be able to view and comment on others' videos. This is done within the Mario Kart 8 software through a feature called Mario Kart TV, not within the Miiverse software itself.

Usage in Nintendo 3DS games
Miiverse has been released on Nintendo 3DS systems as of December 9, 2013. It will eventually have communities from most of the previously released games. Initially, there are communities for: Mario Party: Island Tour, Mario & Luigi: Dream Team, Mario Kart 7, Super Mario 3D Land, New Super Mario Bros. 2, Luigi's Mansion: Dark Moon as well as a few others.

Mario installments with Miiverse
 

Other installments with Miiverse
NOTE: Games shown below are not directly related to the Mario game series overall, but do contain references to the series.