Technology has mostly funneled online identification systems down to a couple of options. On one hand, there's the approach of Xbox, PlayStation or Twitter which lets users sign up for a single account name that they own, but it can't be registered to anyone else. The other, like Discord or Blizzard's Battle.net has people register any name which is then assigned a random four-digit suffix to make it unique. Both are easy and logical and not-frustrating.
Which brings us to Nintendo's friend codes. Originally implemented circa 2006 for the Wii, Nintendo introduced 12-digit numeric friend codes for connecting socially. The system has persisted through the Wii to the 3DS and now the Switch. (It has been especially relevant lately as Animal Crossing has people swapping friend codes.) Nintendo has also partially done away with them, as Wii U and Switch make use account IDs similar to Xbox and PlayStation's setup.
Friend codes aren't especially well-received. Most people view them as convoluted and archaic, a tough-to-remember way of telling others how to find you. That, somehow, was the exact opposite of what Nintendo hoped to accomplish. In a giant leak of Wii information, there's a PowerPoint presentation that argues in favor of friend codes because Nintendo thought usernames weren't simple or comfortable enough.
