Nintendo has opened the door on the functionality of its brand new online app: Nintendo Switch Online. The app will feature voice chat services and game-specific services, such as the newly announced SplatNet 2.
Here is the segment of the Splatoon 2 Direct talking about it.
Here is the official description of the service by Nintendo:
When the Nintendo Switch Online app launches for mobile devices on July 21, players will also have access to SplatNet 2. This Splatoon 2-specific service helps players stay in touch with Inkopolis even when they are away from their Nintendo Switch systems! SplatNet 2 displays information like stage schedules, gear and stats, and even lets users view their lifetime inkage, a feature that shows how much turf a player has inked compared to real-world places. The Nintendo Switch Online app allows users to invite other players to join Private Battles, League Battles, Salmon Run and Splatfest Battles, as well as communicate with those players using voice chat.