I forgot one approach: Charge content creators. An example: Soundcloud. This was very much touted as the best strategy during the Web 2.0 era by thinkers like J

I forgot one approach: Charge content creators. An example: Soundcloud. This was very much touted as the best strategy during the Web 2.0 era by thinkers like Joi Ito. However, I haven't seen it working well for generic social networks. The network has to be build around specific kind of content/audience.