Tencent's WeDoctor seeks to overhaul China health care with big data

As soon as you're diagnosed as diabetic, ads for treatments show up on social feeds. You get alerts on health supplements, maybe nutrition tips. Prompts on insurance policies pop up on your phone. It's a manifestation of the trove of data harnessed by WeDoctor, one of China's most richly valued online health outfits, in an ambitious quest to upend the business of personal care. The ads may not be conspicuous – they can be buried within a pitch about chronic diseases – but the target is uncannily precise: you.