Mobile phone ringtones were once just a minor irritant on public transport. Today, they're a lucrative multi-million-pound industry with member companies being investigated by watchdogs over price, sales transparency and marketing to minors who are unaware of the costs.
Most recently, the astonishing commercial success of a single ringtone has helped to highlight the dangers of expensive premium-rate text and download services.
The Crazy Frog, an offbeat piece of electronica based on the revving noise of a moped, proved so popular as a handset ringtone that it hopped to the top of the UK music charts when its tune was adapted to a dance beat.
However, its success has come at a price. The Independent Committee for the Supervision of Standards of Telephone Information Services (Icstis), the regulator for the premium-number industry, has since received more than 100 complaints from parents and other phone users.
Their grievances concern the lack of transparency over the ringtone download cost and the targeting of the service at young children - customers who are not properly aware of the charges.
Icstis's own industry code demands the opposite: that such deals must be clearly priced and not targeted at those under 16.
However, children can buy ringtones as long as the total charged is no more than a one-off £3.
MBlox, the firm that supplies the service through ringtone contents provider Jamster, is now being investigated and faces a fine of up to £100,000 if found in breach.
"Technology often outstrips consumer awareness in the fast-changing world of mobile phones," says Catherine Bell of Icstis. "It is important that [companies make] clear that subscription downloads like Crazy Frog are not allowed to be sold to children."
Many of the problems with premium-rate text message and download services turn on the difficulty of knowing exactly what you're signing up for.
The process usually starts with consumers texting a word to a five-digit phone number. This triggers the premium-rate service. The download is then sent in one of two ways: either as a direct text to the phone, or in the shape of a password for an internet site that supplies it.
Often, the user will then receive follow-up downloads related to the original ringtone, and since many of these services are subscription-based, the true cost may not be clear until the bill falls through the letter box at the end of the month.
That's why consumer awareness is vital. It's only when the mobile user texts the company to instruct it to stop sending information that the downloads or texts will actually cease.
If no action is taken, the customer can end up receiving scores of unwanted texts - and paying for them each time.
Following a large number of complaints, Icstis is scrutinising industry charging and advertising to make pricing transparency a priority. For example, if the service is subscription-based, this should be made clear on any advertising material or electronic text-message sales receipt.
The intervention comes at a boom time for downloads. Some three million people in Britain change their tune every month, according to Icstis, and last year £317m was spent on downloading ringtones.
There are scores of premium-rate suppliers offering similar services to mBlox, including TXT UK, Ringtoneking and Partymob.
To cancel any subscription, simply text "stop" to the sender of the message.
To complain about any premium-rate phone deals, contact Icstis on 0800 500212 or go to www.icstis.org.ukReuse content