Nintendo is shying away from the two most social features of the Wii U and 3DS.
While Nintendo considers the Nintendo Switch a sort of successor to both the Wii U and 3DS, there are two features from those devices that won't be making their way to the Switch. They are Miiverse, Nintendo's "social network" app that extended across both systems, and StreetPass, a 3DS exclusive application that allowed players to exchange data with other nearby players without even opening up the device.
David Young, Nintendo of America's assistant manager of public relations told GamesBeat says that the lack of StreetPass plays into the idea of the Switch as a home console, not a portable system. The lack of Miiverse is due to Nintendo switching to "other non-Nintendo platforms" for the Switch's social media functions, presumably established networks such as Facebook or LINE.
I doubt too many will shed a tear for Miiverse, but StreetPass was easily one of the coolest features of the 3DS. It was really fun going to a big event or theme park and "collecting" a bunch of people.