2016-07-29 更新：微信群超过100人之后，无法通过扫码二维码方式加入，只能邀请制。因此，以上二维码暂时失效，目前我们有两个QQ群，欢迎点此加入。

Updated on July 29, 2016:
There is a limitation of Weixin Group: You can't join into a group by scan QR-code when a group arrived 100 members. The new member can only be inveted by Group Administrator. So the QR-code in this post is inative now. We have two QQ chat groups currently, you can click here to join us.