In 2012, Microsoft announced that it was closing Windows Live Messenger, also known as MSN Messenger, worldwide in favor of its then recently acquired Skype. There was only a single exception: mainland China. While there was no real explanation at the time as to why China was keeping the outdated service which, obviously, would no longer allow out-of-country communication, it was accepted as just another China thing.
As it turns out, the service was operated by a separate company in mainland China, and therefore was not included as part of the abandonment. That Microsoft brand was unable to handle the mobile messaging craze without the support of the parent company, and Chinese users have found more their way over to apps like WhatsApp in exchange for Messenger. Because of this, the final shutdown was inevitable.
The most popular name in the platform for China, though relatively unknown outside, is WeChat, a product developed by Tencent. The product is so popular in China, in fact, that the Chinese counterpart to TechCrunch, TechNode, has a QR code for their corporate WeChat account on the sidebar of their website. If an AOL partner, which still operates AOL Instant Messenger, is using the service over their partner's service, you know the size and scope of the service.
WeChat's developer, Tancent, has a VP who was originally part of Microsoft's MSN service, heading up the Chinese version of MSN Spaces and MSN Shopping. He left in 2006 to build MSN competitors at Tencent. It could explain why WeChat is having the success that they are, having both the backing of a Chinese company and the leadership of someone who knows the inner workings of MSN.
Either way, it is a sad day knowing that the bubbly blue and green icon is officially over worldwide.