How to find out what song's playing? SoundHound or Shazam? Two know more than one, so I keep both.
But when I updated Shazam it started to do strange things. The "vibrate on tag" option that I switched off insisted on reactivating all by itself. And instead of sitting quietly in the background after I was done Shazamming, it kept going online and ate over a megabyte of data every day even when I didn't use the app. A megabyte or two may not sound like a big deal, but just go abroad and you'll soon find that a useless megabyte per day on an expensive roaming connection adds up real quick.
It seemed that there was no way to stop it. Worse yet, Android insisted on auto-loading Shazam into memory even when I didn't touch the app. And then it went eating data in the background and defaulting back to shaking on tagging.
Edit: The single tag method is only a temporary fix. After a while Shazam picks up its bad habits again.
Edit 2: Like v3.6.1, Shazam v3.8.1 doesn't leak data, but versions 3.8.2 and 3.9.0 do.
• Shazam (Android Market)