The Sparrow mail app icon had been bouncing fine on launching the app till a few days ago but has stopped doing so recently. Any reasons why it might be so? I miss the bouncing dock icon.
Have you set the "Show Icon In" option on the General tab of Preferences to "Only in Menu Bar"? If you have then the dock icon won't bounce anymore and when you have Sparrow open you probably won't see the little hightlight at the bottom that normally indicates when an application is open.
Actually I just set that option back to "Dock and Menu Bar" and my Sparrow dock icon doesn't bounce either.
This might be a bug in the 1.0.1 release they issued fairly recently.