I've been attempting to research social network history (among other things) to get a grip on all real world "trials" beyond the social networks currently running. Beyond the obvious problems with their ad driven business models, The Modem World ends with a decent synopsis of the differences:
[...] unlike the sysops who enabled the flourishing of early online communities, the volunteer moderators on today's platforms do not own the infrastructures they oversee. The do not share the profits generated by their labor. The cannot alter the underlying software or implement new technical interventions or social reforms. Instead of growing in social status, the role of the sysop seems to have been curtailed by the providers of platforms. If there is a future after Facebook, it will be led by the revival of the sysop, a reclamation of the social and economic value of community maintenance and moderation.
Next stop USENET newsgroups.