Wiktionary
n. A telephone number for which an extra charge is assessed to the caller, part of which is returned to the owner of the number.
Wikipedia
Premium-rate telephone numbers are telephone numbers for telephone calls during which certain services are provided, and for which prices higher than normal are charged. Unlike a normal call, part of the call charge is paid to the service provider, thus enabling businesses to be funded via the calls. While the billing is different, calls are usually routed the same way they are for a toll-free telephone number, being anywhere despite the area code used. These telephone numbers are usually allocated from a national telephone numbering plan in such a way that they are easily distinguished from other numbers. Telephone companies typically offer blocking services to allow telephone customers to prevent access to these number ranges from their telephones. In some jurisdictions, telephone companies are required by law to offer such blocking.
Adult chat lines ( phone sex) and tech support are a very common use of premium-rate numbers. Other services include directory enquiries, weather forecasts, competitions and voting (especially relating to television shows). Diplomatic services, such as the US embassy in London or the UK Embassy in Washington, have also charged premium rates for calls from the general public.
In many European countries, for example France, Germany and the United Kingdom, it is common for organisations to operate customer service lines on premium-rate numbers using prefixes that fall outside the scope of the country's premium-rate number regulations. Therefore, in contrast to North America where customer service numbers are typically free of charge to the caller, consumers in Europe often pay a premium above the cost of a normal telephone call.
Computer criminals have used premium-rate numbers to defraud unsuspecting Internet users. One scheme involved inducing users to download a program known as a dialer that surreptitiously dialed a premium-rate number, accumulating charges on the user's phone bill without their knowledge. Another now-uncommon premium-rate scam involves television programming that induces young children to dial the number, banking on the notion that they will be unaware of the charges that will be incurred. One variant, targeted at children too young to dial a number, enticed children to hold the phone up to the television set while the DTMF tones of the number were played. This type of scam was especially popular in the late '80s to early '90s in the United States before tougher regulations on the 900 number business forced many of these businesses to close.