>>9
Public Unix. Also known as "tildes" now, but SDF (and pubnices) precede them by decades.
The idea is to locate (and create) social data onto a headless server that users SSH onto.
It simultaneously resolves a lot of problems. The main issue for mainstream adoption would be creating a frontend that blackboxes the CLI aspect.
Otherwise, the primary thing that Web 2.0 does is many-to-many text transfer--something Unix excels at.