The real assumption here is that facilitating communications will help drive up traffic and thus ad revenue. A commendable initiative by Facebook if you are one of their investors.
Well, as has been demonstrated time and again, there is not always a conflict between "private" / "market" interests and "public" / "community" interests, nor need there be. (Arguably, there's almost never a clash unless the market interests are coupled to political ones, but let's not get into that...)
I'm not saying so much that there is conflict, but I very much doubt that the Facebook people truly believe that this will have any real effect on world peace or that their motives are anything other than money.
