When I started seeing this phenomenon, I knew I had to get back to work on my Mac OS X version of Now Playing.
I added Twitter support for my Windows editions back in 2007. However, that was before Twitter was Twitter and nobody knew what to do with it. Fast forward to today when people are manually typing in their personal "now playing" messages. How barbaric!
I wasn't going to add Twitter support on the Mac edition because of the lack of usage I saw on the Windows side. However, with this #nowplaying trend, it got me excited about giving it a go. Not too much to code other than all the required OAuth stuff that I had to put in. Got that going which has the added benefit of putting "Now Playing" as the source of the tweet. See?
That is a hyperlink to the plugin too. Very cool. Hopefully that raises awareness.
I just pushed out the update today after working on it over the course of a week. So to all you faithful plugin users, get your update on and start #nowplaying!