From the May 2014 issue of Entrepreneur

In an episode of his late-night show last fall, Jimmy Fallon held a Twitter conversation in real life with Justin Timberlake. Littered with spoken hashtags (my favorite: #lololololololololololol), the sketch skewered what happens when companies--and all of us--get a little carried away with tacking these things onto every social media utterance.

But hashtags don't have to be gratuitous and silly. They serve a purpose and can help tell your company's story, share your history and align you with an audience.

In social media, the pound symbol (or hash) turns any word or group of words that directly follows it into a searchable link or keyword on Twitter, Vine, Facebook, Instagram, Tumblr, Google+ and Pinterest. A hashtag is a handy shortcut--a way for people to find, categorize and rally around topics and conversations. So if you want to chat about the return of 24 to the Fox Network this month, you might search for #24Fox to follow the conversation. You can track and follow trending hashtags on the various platforms themselves or via Hashtags.org, which categorizes and gives details for each.

Here are some ways you might consider using hashtags for your own organization.

Share your history. #throwbackthursday (or #tbt) began organically, with people on Instagram sharing pictures of themselves as kids or reminiscing about historical events. Even the First Lady (@michelleobama) regularly plays along with the popular meme, posting throwback photos of herself in college, with her brother as a child or from her high-school yearbook.

Some companies use the weekly ritual as a way to share their brand histories. People magazine (@peoplemag) celebrated its 40th birthday with an Instagram video that flipped through the pages of its first issue. The clip of the March 4, 1974, issue--featuring Mia Farrow on the cover and photos of a young Prince Charles and gymnast Cathy Rigby--saw some 2,000 likes, pretty good engagement for Instagram.

I like the way Toyota posts #tbt on Instagram to show not only the longevity of its vehicles but also to place them in historical context, aligning the brand with American history and values. For example, around this year's Super Bowl, Toyota posted a #tbt photo of its classic 2000GT with the caption, "In 1967, Americans watched the 1st 'big game' and this beauty was on the roads."

Tap into what people care about. The biggest mistake companies make with hashtags is assuming that people want to talk about their dumb brand. Hint: They don't. People want to talk about what matters to them, not what matters to you. While a brand-name hashtag can help lay the groundwork for a conversation (see the #24Fox example), it's generally better for companies to connect with people on social networks by tapping into conversations that are already happening. As my friend Tom Fishburne of Marketoon Studios says: "Brand loyalists are loyal to a brand only as long as a brand complements their own life and priorities."

The New York Public Library (@nypl) did this brilliantly in February, when it tweaked the notion of the #selfie and asked book lovers to post a #shelfie--photos of their bookshelves or favorite library shelves--on Twitter and Instagram. The response was impressive: More than 3,300 people from 14 countries took part.

In March the NYPL did it again, tweaking college basketball's March Madness to hold an author "smackdown" of #literarymarchmadness. Each day the library pitted authors against one another in various "conferences": Triple Threats (Zora Neale Hurston vs. Edna St. Vincent Millay), Real-Life Feuds (Gabriel García Márquez vs. Mario Vargas Llosa), Kid Favorites, Cult Following. The library's 25,000 Instagram followers "voted" for their favorites in the comments.

Morgan Holzer, an information architect at the NYPL, launched the program with Billy Parrott, who runs the library's Art Picture Collection. "Whenever possible, add personality," Holzer suggested when I asked her what other organizations could learn from their efforts. "Followers know there is a person behind the scenes and will get turned off if your post sounds automatic. We like to use humor on the NYPL's Instagram, and people appreciate it. People want to see what you see, not just what they can see."

A simpler (but no less effective) take on this idea is to post business know-how on #marketingadvice or on #whatImreading or travel deals on #cheaptravel--broad keywords with which you'd like your company to be aligned.

Convey your personality. In The New Yorker a few years ago, Susan Orlean wrote that hashtags can function as an aside, "muttered into a handkerchief"--deadpan commentary, humor, sarcasm or context. As she wrote: "I just made out with your husband! #kidding #hewishes #likeIwouldadmititanyway."

Brands convey personality through a kind of social voice and tone. DiGiorno pizza latched on to NBC's special December broadcast through #TheSoundOfMusicLive to live-tweet comments such as "Can't believe pizza isn't one of her favorite things."

TalkTo's tweets often include #NoMoreCalls. It sounds like a rallying cry against robocalls or Alexander Graham Bell, but it's really just a cheeky way to convey personality and align with the company's broader story: The mobile app allows you to text any business instead of calling, so there's no more time wasted on hold.

Hashtags can be a quirky expression of personality--uniquely yours, based on who you are as a brand and how you wish to communicate. Consider them the secret sauce in your content brisket.