We all know what an exclamation mark is, but do we know how to use it? Here is a dictionary definition:

exclamation mark (exclamation point)
noun
a punctuation mark (!) indicating an exclamation.

“One should never use exclamation points in writing. It is like laughing at your own joke.”― Mark Twain

when to use an exclamation mark

Only use an exclamation mark when issuing a command or speaking forcefully! As in the case of the question mark, do not follow this with a period and do not combine it with other punctuation marks. Oh, and only one is needed. Two or three exclamation marks in a row is completely unnecessary. “Interjections (Hey!) show excitement (Yow!) or emotion (Ouch!)./ They’re generally set apart from a sentence by an exclamation mark/point,/ Or by comma when the feeling’s not as strong.”

The exclamation mark didn’t become a standard feature on keyboards until the 1970s. For a fun article on the over-use of exclamation marks now in the age of the internet, read this article in The Boston Globe:
We love this memorable use of the exclamation mark, by one of America’s literary giants:

“Make voyages! Attempt them! There’s nothing else.” Tennessee Williams, Camino Real

We are all using exclamation marks far too much these days, in texts, emails, etc.  Here is one person’s thoughts about this habit of ours:
“Even though I know better than to use stunt punctuation instead of thoughtful language, I often find my hand hesitating over the exclamation point,” confesses Martha Brockenbrough, author of “Things That Make Us [Sic]” and the founder of the blog the Society for the Promotion of Good Grammar. “Should I use one? Does it seem amateurish? Without it, does my e-mail sound bossy and abrupt?”

Some history about the reason exclamation marks became so popular:
“The fact that dialogue balloons in comic books may seem to have an awful lot of exclamation points in them says at least something about the whiz-bang nature of plot and dialogue in this artistic genre, but a more practical reason is that printers in the early 19th century, using the workaday offset presses of the time, found that periods by themselves tended to disappear, while exclamation points remained largely legible.” (Alexander Humez and Nicholas D. Humez, On the Dot: The Speck That Changed the World. Oxford Univ. Press, 2008) about.grammar.com

A exclamation mark (!) is place at the end of a sentence that expresses a strong emotion. Use it for this purpose, and just one is enough!