It's always interesting to see what apps they have pinned or what they use the most (snapchat, instagram, twitter). Generally with tech-related stuff I'm the most knowledgeable and up-to-date family member, but I completely miss the train when it comes to social apps sometimes. I think this is because I'm older, geographically isolated from young people, and grew up without a cellphone at all. I definitely had a phase where I was obsessed with joining things ASAP (remember Pownce?), but I feel like I've been done with that part of my connected life for a few years. I use instagram, but don't follow anyone except immediate family members or close friends, I have 0 exposure to the super popular "celebrity" accounts because I rarely use or search for hashtags. I still don't use Snapchat, and recently one of my brothers was shocked that I didn't use Venmo.
A particular thing that I've found really odd is that I have trouble getting a text response from my siblings, even though I know they have their phones on them and are constantly snapchatting, or whatever. I text a lot, but maybe get one response for every 5-10 texts I send.
I think the one extremely consistent app in my family is Spotify, although it's fairly rare for any of us to use its social functions. From my parents down through all the kids, everyone uses Spotify quite a bit.
The younger siblings don't seem to care about or understand data limits as much. To them, the internet is everywhere, what do you mean it's not free?