Three quarters of young people regularly talk to strangers on the South African social network MXit, raising concerns about the risks for young people on the mobile Internet, according to a study Tuesday. Almost 26,000 users responded to a questionnaire on their habits on the popular platform that claims 44 million users. About one third said they spent most of their time after school chatting on the mobile-based network, while 42 percent speak to strangers every day, according to the report. Three quarters of them speak to strangers once a week, the study found. "Children are incredibly adept at figuring out new technologies," said Aida Girma, head of UNICEF South Africa, which spearheaded the report with Harvard University and the University of Cape Town. "And while they may have technical knowledge, they are not always aware of some of the implications of using the technology." Rather than using computers, MXit connects members through cell phones, allowing them to exchange instant messages practically for free. They can also message in groups, called chat zones, that function seamlessly across other platforms like MSN messenger and Google Talk. People from 13 years can be members, while the largest membership group is 18- to 25-year-olds. Last week South African authorities arrested a man known as the "Facebook rapist," accused of raping two women and killing one that he met through his 14 aliases on the popular social network.