In 2006, I have both QQ, Skype, MSN, Yahoo messenger installed and they all work in China at that time. QQ for friends and family, Skype for Voip calls, MSN for friends in university, well, Yahoo messenger, mostly was used to chat with people outside of China, to practice English.

QQ was huge popular among younger populations at that time, in way I could not understand.

I used MSN most of the time to communicate with my friends in university, but almost all my friends or relatives that were below 20 at that time, who have an IM, is on QQ.

But now most people in China are on WeChat, people are moving away from QQ. And WeChat becomes many people's first IM, for example, my mother in-law who is retired, does not know how to use a computer or how to use QQ, knows how to use WeChat.

I have to say these guys are onto something. Yes, they were copycats in the beginning, and yes, their current counterparts outside are blocked in China, but I strongly doubt the theory that if facebook, google etc are not blocked in China right now, they would be successful in China. After all, they had their chance before, and they blew it.