Contributors will have the option of either being paid directly in ether, or being paid in "community tokens" which can be immediately or later exchanged for ether according to a bancor-style exchange protocol.
Honestly, a lot more, at least until we get them right.
I think we are going to see a cambrian explosion of crypto social media platforms as people experiment with different incentive structures, and learn what kind of content is created by particular structures.
And building the initial momentum is definitely going to be a big challenge, but one that will be mitigated by the reward system of a community-owned platform. The value of a social media platform is not in the software, but in the social network. With cryptocurrrency-based networks, it will be easier than ever for users to share in the fruits of creating that network.