I was just looking at Personalized Search History and I see that "Music" is one of the categories for which you can allow search indexing. Is this new? Or does it hint at a new service. I know that they have music OneBoxes, but the other categories (Web, Images, News, Froogle, Video) are all search services, not OneBoxes.

I'm actually not sure now that I've actually looked at it. I'm sure someone else on here has an idea. The strangest thing I found is that when I did a search on Google Music Search http://www.google.com/musicsearch?q it didn't show up in my Music Search history.

it's a log of the songs you play if you use google talk and have it show your currently playing track

Oh so it's for Google music trends? Still, I've used that too and there's nothing in my history

So, if they are indexing our music tastes, do they plan to provide recommendations at some point?

Maybe now they've partnered with two companies to provide music videos for free, they'll suggest Music Videos you could watch.