I don't understand. I asked for a use case. You gave me a glittering generality. What concrete task that i might desire to achieve in life can be done with Facebook but not the other tools?
Pretty much everyone who has a facebook has a phone, so I can communicate just fine with Facebook users
None, but evidently the point I was trying to make was a bit too elusive — it is the userbase and concentration of information it forms that is itself the use case or desirable feature. FB's walled garden IS the tool.
I don't myself agree with it - I'm in your camp, thinking there're far better existant tools out there. I just know from my own experience I'm 'missing out' on stuff shared or put in there by people locked into a domain I do not myself have access to.
Pretty much everyone who has a facebook has a phone, so I can communicate just fine with Facebook users