Most often, quotation marks are used to show someone's exact words. Sometimes, they also signal sarcasm or irony. In most cases, there is nothing especially unusual about this little punctuation mark.

This is the Grammar Guy column, a weekly feature written by Curtis Honeycutt. I can think of a few things off the top of my head that I hope never to use: math, a fire extinguisher, Pepto Bismol and ...