I don't think that Asia has proven its ability to innovate in the internet/messaging space. It's that significant cultural, language, and (in the case of China) legal barriers make it hard for Western companies to compete there. But at the same time, almost none of these companies have shown the potential to expand outside of Asia, and the vast majority of them have not even been able to expand out of their home countries.

Rakuten has tried to grow in the US market using its purchase of Buy.com, but that's not working, partly due to a disastrous rebranding. They also had a failed venture in China. So Viber may be successful if they just leave it alone, but trying to use it to make Rakuten better known in the West would be a horrible idea.

Naver (Korean) has the Japanese messaging service LINE (which was created by some of its Japanese employees at its Japanese subsidiary), but can't gain any other ground. And I definitely can't see the Chinese internet companies becoming successful in Japan or South Korea, given their penchant for censorship and nationalistic differences.