Chinese users of the iMessage app are complaining about a recent rise in advertisements of grey industries such as gambling and lotteries, reports influential Chinese media observer who goes by the online name dongdong-note.

Photo of an iPhone user shows off the functions on iMessage [Photo: IC]

Users are questioning how spammers are able to access their phone number, and also why Apple ID and why the company has failed to offer effective filtering measures beyond reporting the spammers' number.

A manager from a company which provides direct marketing services (spamming) has told dongdong-note that since many smartphone brands have developed group message filter functions, and because the three main telecommunication operators in China offer "No Disturbing" services, sending advertisement via group message is not as effective as before. Thus, he says iMessage becomes an ideal vehicle for spammers.

The group deliverability rates on iMessage can reach 60%, said the manager, with each delivery earning the company 0.1 to 0.3 yuan (1.4 to 4.3 US cents).

A technician from another spamming institute is quoted saying it is easy to get users' phone numbers and Apple ID, as well as indications of when their iMessage functions are activated. He notes this is all acquired through shady, and illegal, means.

Xu Changwei, technician at a technology park in Shenzhen, argues the most effective way to filter out spam is to stop using iMessage.

But because many companies use iMessage through their business, simply closing the function is impractical.