Online pornography addiction involves pornography obtained via the Internet. Psychologists who support this concept argue that it is stronger, and more addictive, than ordinary pornography addiction because of its wide availability, explicitness, and the privacy that online viewing offers. In order to satisfy their addiction, addicts are said to regularly spend extended periods of time searching the internet for new or increasingly hardcore pornography.
Take a look at these resources:
http://www.no-porn.com
http://en.wikipedia.org/wiki/Pornography_addiction
http://pornaddictioninfo.com/
http://www.utdallas.edu/counseling/selfhelp/porn-addiction.html
http://www.wired.com/science/discoveries/news/2004/11/65772
http://www.msnbc.msn.com/id/6525520/