A number of researchers have explored the demographics of the different kinds of Internet users in relation to online sexual and/or relationship activity (i.e., Cooper, 1998; Griffiths, 1999; Young, 1999). Cooper, Putnam, et al. (1999) put forward a continuum model of people who use the Internet for sexual purposes (recreational users, at-risk users, and sexual compulsive users):

Recreational users
These people access online sexual material more out of curiosity or for entertainment purposes and are not typically seen as having any problems associated with their online sexual behavior.

At-risk users
At-risk users are those who, if it were not for the availability of the Internet, may never have developed a problem with online sexuality. Cooper, Putnam, et al. (1999) claim that for these people, the interaction between the AAA factors and underlying personality factors leads to patterns of behavior that may develop into online sexually compulsive behaviors.

Sexual compulsive users
Are people who use the Internet as a forum for their sexual activities because of their propensity for pathological sexual expression.

A profile of very severe problems exists for 1% of users and 40% of these extreme cases of dysfunction are women. (Cooper, 2000)

In a survey of 9,177 Internet users, researchers found that 8% spent 11 hours or more per week engaged in online sexual pursuits. (Cooper, Putnam, Planchon, and Boies, 1999)
Cooper (2000) describes the following as at-risk to develop cybersexual addictions:

Severe cybersex addicts were: (Cooper, et al, 2000)

In terms of demographics, overrepresented groups included being:

One study was done in an outpatient psychiatric clinic. in which 19 males and 21 females were referred primarily or exclusively for problematic cybersexual activity. These typically involved masturbating or self-touching while communicating with someone over the Internet: (Schwartz and Southern, 2000).