There have been some shock in Japanese internet users when Mizuo Sugawara, the director of Japanese Society for Rights of Authors, Composers and Publishers also known as JASRAC, said posting portion of lyric on Twitter can be subject to copyright fee payment. It seems to be bit ambiguous how this can be enforced, as what constitute singing in twitter can be very difficult to determine. You could be unknowingly using part of lyric without realizing about it.
I think JASRAC will be more likely be seeking for blanked licensing, similar to what they have done for YouTube and Last.fm.
That’s quite interesting, as I’m affiliated with ASCAP, which is in agreement with JASRAC, if someone sings my creation on twitter, do I get a piece of pie, too?