Bread-and-circus show

Judith Shulevitz used the phrase "bread-and-circus show" in a diary entry on Slate today, and having never heard this expression before, I was wondering what its origin and meaning might be.

Thanks in advance for any assistance.

From Merriam-Webster Online:

Main Entry: bread and circuses
Function: noun plural
Etymology: translation of Latin panis et circenses
Date: 1914

a palliative offered especially to avert potential discontent