A friend showed me Minitel in 1994, and I was half-surprised, half-not-surprised that even on this entirely text-based system, there was still porn (or at least, "visual erotica"). Human nature, eh?
Xavier Niel (https://en.wikipedia.org/wiki/Xavier_Niel) started his empire with a sex oriented chat service.
In 1998, Minitel generated €832 million ($1,121 million) of revenue, of which €521 million was channelled by France Télécom to service providers.
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https://www.nouvelobs.com/tech/20170804.OBS3007/l-age-d-or-d...