Other social network imports haven’t caught on in Japan like Twitter has, and it may have to do with the un-bird-like translation:

“It’s telling that Twitter was translated as ‘mumbling’ in Japanese,” [consultant Motohiko Tokuriki] said. “They love the idea of talking to themselves.”

I can’t imagine a “mumblr” catching on in the English-speaking world. Maybe the art of the mumble is more respected in East Asia.