Dial Q2 was NTT's premium-rate information service launched in 1989. Calling 0990 numbers provided weather, horoscopes, stock prices, sports results, and adult content via voice, with information fees added to phone bills.
Dial Q2 caused serious social problems in the 1990s. Children repeatedly calling adult lines generated monthly bills of hundreds of thousands of yen. Malicious "dialer" software disguised as internet access points secretly connected PCs to Dial Q2 or international numbers, causing unexpected massive charges.
NTT responded with PIN-based call restrictions and minor access limitations. However, internet adoption eliminated demand for phone-based information services, and NTT discontinued Dial Q2 in February 2014.
Dial Q2's lessons echo in today's 0570 "unlimited plan exclusion" issues and smartphone app billing disputes. The risk of "unknowingly incurring high charges" persists in different forms. See extinct phone numbers for the Dial Q2 era.