This is what it comes down to, isn't it? That's all of facebook's problems.
The success of Instagram and WhatsApp comes from them being less connected, that's their core feature. I don't even mind facebook owning them. I like that the big trend is moving away from documenting every minute of your life in an online repository. Instagram is its own, surreal thing and WhatsApp is basically texting.
There are a bunch of people trying to make apps that forget over time, eventually, one of them will figure out a way to mass market. Heck, I spent last Saturday at the top of HN with one of those that I made, Aether. [0] Prior HN discussion: https://news.ycombinator.com/item?id=18370208
Incidentally, this was exactly one of the problems that Google+ was trying to solve with its "Circles" concept.
A lot of people don't want their daily musings to be on the "permanent record," regardless of age group, and Facebook is almost a victim of its own success -- it's too good at connecting people by loose ties and encouraging this problem. And then it's not long before you have a huge list of Facebook "friends" which include actual friends, family, extended family, bosses, ex-bosses, co-workers, etc. Now, imagine putting all of those groups of people at your dinner table and try to think of topics you'd be open to discussing among all of those disparate groups.