In Splatoon 2's case, the Switch Online app lets you chat with friends, see rankings, keep track of wining stats and of course, organizing online group or private matches. On Thursday morning at 10 AM ET, Nintendo is going to reveal some new features that will be coming in the sequel.
Splatoon 2's Splatfests are kicking off before the game even launches. I just checked to see if the demo client is downloadable yet and it wasn't, but you might have more luck depending on when you're reading this. That app will, appropriately enough, be called Nintendo Switch Online, according to a press release. All Splatoon amiibo also reward exclusive gear, and can be used to save gear and weapon loadouts. It'll come in handy when you want to analyse your strengths and weaknesses! The application allows you to arrange online gaming sessions with your friends as well as chat with them in-game. It looks like friends can be invited from your social media contacts, your Nintendo Switch Friends List, or from a list of people you've battled against previously. In addition to that, Nintendo plans to hold regular Splatfests for Splatoon 2 for two years after its release.
The store is still getting ready for its grand opening at the moment, but should be available in a future update so check back soon!