Topic: Computing history
One of the projects mentioned in Ted Nelson's 1974 Computer Lib/Dream Machines was the Bay Area computer bulletin board system Community Memory that ran from 1973 to 1977. Here is an interesting passage from a description of Community Memory that ran in Creative Computing magazine:
Students began to use the system immediately in their search for housing, and as use of the system grew, so too did its data base. Musicians found others to practice with, buyers and sellers of instruments, and were even able to form new groups. People began to use the system to assemble car pools, organize study groups, find chess partners, and pass tips on good restaurants.