Though really my point was this: it isn't the case that you need to continually re-grab the same users, it is the case that there are continually new users to grab.
I don't think we are mercurial but that we have less experience and therefore are much more willing to try new things. Snapchat is way better as an outlet to post more regular things you are doing to your friends because it is ephemeral.
Why? Because we all look back and see all the stupid stuff we posted when we were younger. The only reason I haven't deleted my facebook to delete all of that old stuff is because Facebook's other offerings are pretty good. While I hardly know anyone that posts regularly to facebook anymore, almost everyone uses facebook messenger and groups to communicate in isolated groups.
Snapchat has been blowing up because it fills that niche of "I want to post more updates about my life without really having to worry about how those updates will be interpreted in the future".
Do you also not do those things over common communication channels outside of talking face to face?
I'm genuinely curious because I literally don't know anyone under 30 that has never done anything that they did not want recorded in history forever.
It's not that I have posted anything on facebook/instagram/snapchat... that is really that bad/embarrassing. If it were all posted on the front page of the NYT I would probably go through life just as normally (albeit, quite a bit embarrassed by it). I would just prefer to minimize that risk.
That's where snapchat fills the niche. It allows me to speak more freely with others with less fear that everything I say and do will be pulled up years later completely out of context.