Facebook Dislike Button Is a Fake—And I Dislike That! [PC World headline]
The rapper-actor was cleared of all charges and declared, “That’s what I’m talking about!” [Gothamist]
If things aren’t going the way you want, speak up! [Jezebel.com]
An exclamation point can be placed in square brackets within a quotation to express the author’s amusement, shock, or surprise at what is quoted. For example, here we are quoting from an article recently posted on the New York Times website:
I’m looking for reader input on whether and when New York Times news reporters should challenge “facts” [!] that are asserted by newsmakers they write about. [New York Times]
In online writing, writers sometimes use exclamation points to make it more obvious that they’re being sarcastic—for example:
Make sure you donate to Reid’s campaign, as it’s absolutely vital that this Good Democrat wins! [Salon.com]
Although exclamation points are useful for the above purposes, many writers take a less-is-more approach, preferring to provide emphasis through word choice and sentence structure.