1., Self-updating rolodex for sales people. 2., Recruitment tool.
It works for both, no real competitor in sight due to the massive network effect.
Some niche networks are doing ok, like Xing in DACH region. Not aware of anything special in China, guess everyone is on WeChat anyhow.
LinkedIn is almost entirely worthless without the occasional good lead from a recruiter. I find it's mostly drowned out by the huge amounts of insignificant skin peddlers who dole out one worthless lead after another, looking for some fresh skin to peddle.
below the marketing language this is exactly those 2 points. guess it is easier if you work in enterprise, this business speak is a different language. pretty verbose, low information density.