"Hypersexual Disorder and Preoccupation With Internet Pornography": http://ajp.psychiatryonline.org/cgi/content/full/158/10/1590
This is a short, not technical view that details a bit about problematic hypersexual pornography use and some examples are mentioned.
From the above reference: "Fairly recent studies have suggested that "pathological sexuality" is far from uncommon and can be associated with considerable morbidity (3, 17). The disorder appears more common in men, and patients may be seen with a range of different behaviors, including compulsive masturbation, excessive use of printed or telephonic pornography, and pathological use of the services of sex workers. As with impulse-control disorders, although the symptoms are gratifying, there is also typically an element of ego dystonicity. Comorbid diagnoses include mood disorders, anxiety disorders, and substance use disorders. Symptoms may severely affect family, social, and occupational function, and negative consequences include those of sexually transmitted disease. There is clearly a need for appropriate diagnosis and treatment of such patients."
If you can also identify with any of those, then you may have a problem...