I'm not sure if you are in this demographic, but a lot of people I know born in 1999-2003 or so in the US used snapchat as a primary method of communication for many years, and a large part of it was keeping up "snap streaks" of sharing one photo a day with many different friends.

This is one thing for all of the pairs of genuine friends doing this, but I also have two friends who I introduced to each other exactly once, and who have never spoken since, who have a 6 year snap streak together, and both of whom have streaks like that with dozens of other people, many of whom are virtually strangers.