Ben Thompson, a month and a half ago on his blog, stratēchery:
If we accept the thesis that messaging is the foundation of social on phones, and that messaging is inherently personal, then that means Facebook has a pretty significant brand perception problem. Their definition of social is public broadcasting, a definition they have reaffirmed both through word and deed. Users have learned that nothing on Facebook is personal or private; why would they expect to use Facebook for messaging? It’s not just that other apps are better at messaging; it’s that Facebook’s carefully cultivated value proposition is in direct opposition to messaging.
So this is pretty old news, but it echoes something I noticed just this morning. I sent a friend a message on Facebook and even as I sent it I seriously thought to myself, "hey, is this going to show up on somebody's timeline?" How crazy is that? Facebook has created a platform so unpredictable and so weighted against privacy that I seriously questioned whether a direct message to someone might (accidentally or "accidentally") end up public.
Obviously Facebook would assure me that they'll never change their security settings (retroactively) so that my private messages would suddenly show up on my profile page. And that example is likely too extreme to pass the smell test. But their entire reason for being is "sharing", and they've built up a pretty serious history of erring on the side of everything-public-all-the-time. At this point nothing would surprise me.
So that's (one reason) why I barely use Facebook. And one reason why Ben thinks the company is in serious trouble.