Turns out that a lot of people I knew posted huge life updates that I completely missed out on. I asked them why they didn’t tell me and they were confused. They said the posted it on social media. I can’t speak for everyone, but I know a lack of social media meant that I have lost touch with old acquaintances completely. I have a few close friends and that’s it.
Maybe that’s an ok tradeoff to make, but it’s worth knowing that before getting into it.
To me, it seems like if someone has so many friends or is so busy that they need to manage their life using this strategy, you probably aren't going to have much of a connection anyway.
In such cases, there's still some reason for the two people involved to at least have a general idea of what's going on in other people's lives, and even reach out should there be something significant, such as a birth of a child or a loss in their families, etc. Without the broadcast aspect, once communication has ceased for some amount of time, it is very difficult to restart it, at any level.
As an introvert, I still find broadcasts weird, because there's that tingling notion that people wouldn't care anyway; and was one of the reasons I ceased to be on social media many years ago. However, I understand why some people choose to do things differently.
(There are similar anecdotes throughout this thread, I'd encourage you to read it for perspectives on this matter.)