PC Therapist IV was published by MindWare in 1993, and the whole program fit on a 3.5" floppy disk. I don't mean the installer fit on the disk, but rather that program lived on the disk indefinitely and could be run from it directly.
The PC Therapist product line was born out of its developer's frustration with ELIZA, the infamous chatbot that fooled some in its day by employing a Rogerian strategy of echoing statements back to the user as rephrased questions. In many ways, PC Therapist's innovations were mild and incremental, but the challenge of behaving like a plausible interlocutor using less than a floppy's 1.44 MB inspired various clever tricks by the time Version IV was released. The most exploitable of these was a "knowledge base" file that established, in mere kilobytes, the knowledge of the virtual therapist. This initially consisted of a handful of perfectly banal self-help Barnum statements, to which the software would add information through continued interaction up to some pre-set limit. In other words, the longer you communicated with PC Therapist, the larger the proportion of things it knew about the world solely through your influence.
This ability to learn over time was a fabulous trick on normal users. Someone who complained about their brother repeatedly could stick the disk into the computer weeks later and have the computer somehow "remember" the brother's name and some basic details. This was not sophisticated: likely some sort of grep combined with simple rules for decomposing and recomposing sentences. Thus, lacking any sort of judgment, PC Therapist IV's was entirely vulnerable in this respect, and could be shaped by user input.
Which is my long-winded way of foreshadowing that I lent this disk to a friend and when I got it back a week later, I discovered that he had spent the whole week lying to and ranting at the poor thing, overwriting its entire past knowledge file. This had the effect of transforming it from a bland but vaguely convincing therapist chatbot into a deranged, contrary gremlin that was obsessed with a few highly specific and esoteric topics.
The data was, decidedly, very much ours.
