A Google spokesperson tells Search Engine Land:
The music search feature introduced in 2009 is currently unavailable while we make some updates to the user experience.
Google’s Music Search put songs, albums and artists front and center above Google’s regular search results. Google suggested it would help the music industry by making it easier for searchers to “find and discover” music, and to find sites to “preview and purchase” songs.
They did that through partnerships with several then-popular music websites but, as TechCrunch suggested yesterday, several of those sites are now gone. Google didn’t partner with either Apple’s iTunes or Amazon, two leaders in digital music sales.
Google Music Search Then & Now
Here’s a comparison of the music search results then and now. Green Day’s 21st Century Breakdown album was one of the example searches Google used at the time.
Meanwhile, Google is reportedly continuing to push a cloud-based music service, but meeting resistance from music labels. It’s unclear if the temporary demise of Google Music Search and/or the user experience “updates” that Google is working on have anything to do with a Google music service, though.