There are several tools available to evaluate health websites. Most of them list criteria that reliable websites should meet. Here is a summary of the main criteria.
Internet
Diagnostic Criteria for Internet Addiction
Behavioural addiction affects a vast number of individuals and occurs when people find themselves unable to control the frequency or amount of a previously harmless behavior such as love, sex, gambling, work, internet and chatroom usage, shopping or exercise. Behavioural addictions are considered impulse-control disorders and share many underlying similarities to substance addictions, including aspects of tolerance, withdrawal, repeated unsuccessful attempts to cut back or quit and impairment in everyday life functioning.