NPR has an interesting piece on how the internet shaped the American rave scene in the 90s.
At first, the connections were done the old-fashioned way. “By 1994, there was already kind of an established network of party-throwers and partygoers [in Detroit],” says Rob Theakston, a Detroit rave veteran. “At that point, the scene was maybe 200 kids max. Everything was very phone-based. [You’d] call the phone lines the day of to get directions, and even then, a lot of the direction lines would just give the vicinity because you would already know: ‘Oh, Harper and Van Dyke — that’s the old theater. We know where the party’s going to be.’ They wouldn’t give you the exact address for the authorities to find out.”