Exclamation Marks (also called exclamation points) are used to give emphasis to a statement and to indicate a command or an interjection:
You should read my latest blog post! (emphatic statement)
I’m so happy to see you! (emphatic statement)
En garde! (command)
In each case, the exclamation mark indicates a strong feeling or emotion.
In academic writing, exclamation marks are exceedingly rare. The tendency is to let the words speak for themselves. Here’s an example where you might want to resist the temptation to add extra emphasis:
The ANC, the ruling party in South Africa, condemned the novel Disgrace because of its depiction of young black men raping a white woman.
Adding an exclamation mark makes the sentence seem sensationalistic, which is probably unnecessary.
How do exclamation marks function in relation to other punctuation marks?
Just as with question marks, the rule is that an exclamation mark should not be combined with other punctuation. Here are some examples:
Incorrect: “Come to my party!,” she shouted.
Right: “Come to my party!” she shouted.
Incorrect: The latest opioid to hit the streets is much more powerful than fentanyl!.
Right: The latest opioid to hit the streets is much more powerful than fentanyl!
There are some exceptions. It may happen that an abbreviation precedes the exclamation mark:
I’m inspired by Martin Luther King, Jr.!
Similarly, things can get complicated when a name includes an exclamation mark:
Do you like How The Grinch Stole Christmas!?
If you find that this looks awkward you can always rephrase the sentence.
Finally, there is some dispute about whether you even need to include exclamation marks that are part of company names (e.g., Yahoo!). Some editors feel that retaining the exclamation mark is somewhat like giving the company free advertising.