30 years ago, Band-Aid put out a song called "Do They Know It's Christmas?" to raise money for a growing famine in Ethiopia. This song, among other things, prompted many people to give money to help with the famine, but this probably ended up making things worse. The government of Ethiopia was very corrupt, using the aid to help supporters while leaving political opponents to starve. In addition, the lyrics of the song received criticism for being patronizing and painting all of Africa with the same brush.

Just recently, they've changed some of the lyrics and repackaged the song to help with the Ebola outbreak. It's being criticized for the same reasons.  This article explains it in greater detail - I'd recommend taking a look.