[japoneris]

- Interoperability: FaceBook / Twitter and all other social network take their advantage from the network effect / the winner takes all, not because it is "good", "private", "secure", "beautiful", "user friendly", but because they have the critical mass. A decentralized social network must be like bittorent. You have many client, choose the one that suit you the best, and share data with other whatever their client.

- Add-free Business model: Big question in how do you monetize the system, making it viable. Maybe the people contribute in storage, storing the data of people they interact with to enable availability, and contribute depending of their possibility.

- Data ownership (a lot of concern for some tech people, but for the majority, I think they don't really care / understand the problem)