It's fair to say that when it comes to online discourse we live in the Golden Age of Snark. (That's snark as in "snide commentary," not the imaginary animal of Lewis Carroll's nonsense poem "The Hunting of the Snark.") When every statement you make is open to sarcastic rebuttals, sometimes the best policy is to ridicule yourself before someone else has the chance. Nowhere is this more true than Twitter, where the convention of the "hashtag" has been pressed into the service of self-mockery.

A hashtag, for the non-Twitterati, is a word or smashed-together phrase preceded by the hash symbol (#), originally devised as a way to keep track of the flow of subject matter in the Twittersphere. But the function of the hashtag has morphed significantly since Chris Messina and his colleagues began using it in 2007 as a method of indexing topics of interest. (Even the word hashtag has moved in unexpected directions: whereas it has typically referred to a string of characters prefixed by the hash symbol, now it often gets used for the symbol itself, including in Twitter's own help documentation.)

In this Sunday's Boston Globe, I take a look at how hashtagging has become the perfect vehicle for self-directed sarcasm, used by celebrities and common folk alike. Take a look at how a pro does it: the tech-savvy actor Wil Wheaton (who began earning geek cred back when he played Ensign Wesley Crusher on Star Trek: The Next Generation) recently tried to link to pictures of himself on the set of The Big Bang Theory. After he gave the wrong link, he tweeted, "I love that I'm trying to be all clever, and then I epic fail at basic linking. #lessonsinhumility #facepalm #hashtag." (If his use of "epic fail" seems unusual, check out my On Language column and Word Routes followup on recent transformations of fail.) Wheaton uses the self-effacing "#lessonsinhumility" hashtag, followed by "#facepalm" ("the act of bringing one's palm to one's face to indicate embarrassment, exasperation, or despair," says Wordspy), capped off by a meta-ironic touch, a "#hashtag" hashtag.

By the way, though Wheaton here is properly abashed in the face of a blunder, note that his purpose is to draw attention to his guest appearance on The Big Bang Theory. Thus his tweet could be characterized as a humblebrag, a wonderful neologism that has gained currency this year thanks to the comedian Harris Wittels, who created the Humblebrag Twitter feed to compile flagrant examples of "bragging that masks the brag in a faux-humble guise." Wheaton has been singled out by Wittles for humblebragging twice already.

Or consider the Twitter auteur (and humblebragger extraordinaire) Kanye West, who last year tweeted, "You have to balance ignorance with intellect! Can't have school with out recess! #Greatesttweetofalltime." To an outsider, the hashtag might seem like pure arrogance, but anyone following the rap star's career would have recognized it as a tongue-in-cheek callback to his interruption of Taylor Swift at the 2009 MTV Video Music Awards with the message that Beyonce had made "one of the best videos of all time!" Thus in a single hashtag Kanye managed to poke fun at his own foibles with his typical mixture of bravado and self-skewering.

One ironic hashtag that has been particularly successful is "#firstworldproblems," appended to a complaint that is obviously frivolous in the grand scheme of things. The hashtag has played a big role in popularizing the "First World Problems" Internet meme, which has generated its own Tumblr blog, a section on the user-generated site Reddit, and not one but two rap parodies: one by the Brooklyn "nerdcore" hiphop artist MC Frontalot and one more recently by Zach Katz, a.k.a. "Funnyz," a 17-year-old YouTube sensation from Virginia. A typical line from Katz's rap: "My fridge is so full I have to reach way back, and my sports car doesn't have an audio jack." Meanwhile, on the blog "White Whine," the comedian Streeter Seidell mines this vein of humor one silly grievance at a time. And then there's the "#whitegirlproblems" hashtag, which has its own following; the creators of the "White Girl Problems" Twitter feed will soon publish a pseudo-memoir from the perspective of their laughably privileged protagonist, Babe Walker.

Not everyone is a fan of such race- and class-based self-mocking hashtags. Marcus Hunter, a sociology major at Columbia University, recently said in a Tumblr post that while he often finds hashtags like "#whitegirlproblems" funny, he is troubled that "calling attention to the privileged mindsets and behaviors of whites is only able to happen in a jokingly meta or ironic way." Hunter hopes that such privileges can be critiqued and analyzed with "the same verve and enthusiasm" as when they are ridiculed. Self-mockery might then make way for a deeper self-examination, all with the help of those little hashtags.

I leave you with Zach Katz's "The First World Problems Rap" (1.35 million YouTube views and counting).

Update: My Boston Globe column is online here.