I mean it depends. One thing about 1918 is that most people who actually lived it are ... Dead. This means essentially that the stuff that lives on are things in the media reports. We have photos of guys in trenches and people in masks and anti mask leagues (which were formal clubs in 1918). On the other hand, judging from my family, the stuff we actually remember to pass down as oral history are things that affected us personally. My great grandmother caught the Spanish flu and lived. They boiled the silver wear (which probably didn't help because it's a virus, but what would a young Polish girl know). From the Depression I have stories of my great grandfather feeding random kids in Chicago and not charging some people for the milk he delivered. Also he had a blind horse.

I think people who personally lost jobs and houses will remember. People who couldn't have their weddings the way they wanted will remember (my grandparents couldn't get some stuff because of WW2, so they made their wedding meal brunch after trading ration points), they'll remember if they participated in protests. I think 1/6 will join 9/11 and the JFK assassination as a "where were you when" thing. For the record, I was watching the speeches, Ted Cruz put me to sleep, and I woke up 20 minutes later hella confused.

Stories that happened to you, you'll remember. Marquee moments that get press will be collective memories.