I was luck last three weeks in Shanghai China where I was there as hometown more than 25 years. This is a 2nd time of last 2 years to return there. Always I do not have time to write some experiences because of difficult timing-up.
OK direct to the topic what I want to say: NO Google, NO Facebook. I think that I can't do more developments and codings there because I was so familiar with Google things like Android(Play Services), GAE etc.
But the Chinese mobile-world is dynamic and boom. As you take a taxi you find that drivers use different taxi-apps which are so simulated against Uber or mytaxi. There're so many Androids, not only the XiaoMi, MeiZu but also other different unknown devices, and app-market is also amazing large. You'll see different taxi-apps as examples. Also the WeChat occupies whole "chat-world" instead of Whatsapp here in west. In the network-world the Weibo takes over the places of Facebook and Twitter. The Weibo is an akin to a hybrid of Facebook and Twitter. Of cos the Baidu plays a role as Google there and almost all normal users including developers use it. I think Chinese can do more and more when the west creation and innovation are adapted there. HmHmHm.... also an interesting thing, I don't have a mobile-number, but I can use free network everywhere, although I've to cherry-pick an available cell-phone to get password if I must do. But in some places like hotels or restaurants I do not need them. By using WeChat I can forget direct phone-call, SMS.
Fazi! I must learn and track the market of China, otherwise I'll be lost there :)