QQ is great in terms of a chat vehicle.  It is also great in terms of being spyware, a virus generator, an all-around PC hijacker and the lack.

I do use QQ but I use a version that has been sanitized by the Malaysian government.  Just search through google.  You can find the version there. 

Is QQ the Chinese version of Facebook?

I've never looked at Facebook.  What's it good for?  I know it seems to have caught the imagination of most of the worlds' population, but not mine.

Email is one of life's great inventions and a marvellous method of communication.  

I'm often asked for my QQ number and when I respond with "what's QQ?", the asker thinks I'm some kind of freak.

Har!

And then my "I don't know" response to the what's your telephone number really blows them away.

Har!!

I do use the QQ protocol, but not the QQ software, which has grown over the years as a bloatware that tries to take over your whole system at every install, probably feeding Tencent with everything you do online. Everytime I install QQ, I need to castrate three or four other executables that try to connect to the internet for no useful purpose at all.

Just like any other Chinese software including pinyin IME like Sogou and video streaming stuff. They might be convenient, but by using them you are willingly handing over every information you store. Don't forget they do not see privacy or ethics as a topic at all, and Tencent might be doing a LOT of PR for improving their image, they are not to be trusted, never.

I use QQ international because company wanted me to so i can communicate with my colleagues 

I left work and i'm leaving China so once i'm out i will definitely not use it again

I used to use it 4 years ago, but now it is less popular as most people now use wechat instead (which is made by the same company as QQ).

As the poster above, I used to use it four years ago when I first came here, but now I only use Wechat. Much more convenient.