No doubt, but the fact file sharing networks were and still are largely self-hosted proves that people will have no issue doing the same to get a copy of some movie or music album. So self-hosting your FB-like wall or Twitter-like timeline shouldn't be much harder. If anything, I think it would be easier since the remaining data that would be stored would be relatively small (thinking of Vine-like videos, photos like you have on Instagram, etc) with the rest just being hyperlinks. Hell, I think you could make them all hyperlinks and put storage in some other distributed protocol if you have to. In any case, it's not a technical problem in my opinion, it's just a problem of making such a platform as easy as installing it on your phone without a second thought beyond are you JamesBond007SexyTimes123 or whatever you silly handle would be.