Robin Hamman appeared live by phone from the UK on South Africa's Radio 702 Internet Show with Kevin Garber on 25 April, 1997. The sound quality of the tape I was given of this interview is poor, so I've made a transcript of this 15 minute interview.
Real numbers are hard to come up with and that's largely due to the anonymity of the Internet.
Also, the wide variety of places that cybersex chat can actually occur. It can occur on web sites that have chat options, online services, MUDs, many places. It's hard for me to give you a definite number. Now not everyone who is using the Internet or online services is going to be using the chat rooms so that I can meet them and speak with them there, so it is really difficult to say exactly what percentage of these people are actually having cybersex. They were all very willing to answer questions online, as I'm sure you found Robin.