Five years ago, the owner of a taxicab company might have had little idea that a new business model was about to shake the very foundation of his or her enterprise. In theory, taxi operations seemed immune to the digital disruption sweeping other sectors of the economy. One might forgive a taxicab company owner for thinking in 2009 that no social media platform or mobile app could possibly compete with a driver and a car roaming the city.

But, of course, he or she would have been wildly wrong. When Uber cropped up and connected drivers with ride-seekers, digital platforms had unlocked a powerful sharing economy that changed the way consumers viewed taxis, hotel bookings, hiring practices and even dog sitting.

Marketers today are the taxicab companies of 2009. This field is so hands-on, creative and content intensive, many marketers don't comprehend that a digital disruption could come along and turn it all on its head. But the same sharing economy that transformed the way people see taxis is now upending marketing.

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The smartphone-powered creative department. Just like Uber empowered anyone with a car to become a taxicab driver, user-generated content platforms are allowing any consumer with a smartphone or internet connection to become the creative department in a new marketing model.

The taxicab companies of marketing will continue to invest large amounts of money on professional photography, creative agency fees, videography and traditional advertising. But they will find themselves competing directly with the Ubers, the companies that crowdsource their marketing material from millions of empowered customers.

Companies that do not evolve to take advantage of the millions of smartphone-carrying consumers intent on interacting with brands will find themselves saddled too much with the costs of infrastructure (akin to owning taxicabs, employing drivers and running dispatch centers in a world where a simple digital app directly connects ride-seekers and drivers). They will find themselves spending large amounts of time and money working with professional photographers, videographers, copywriters and creative directors, while more nimble brands launch consumer-marketing efforts that in a matter of days collect and showcase thousands of authentic photographs, videos and testimonials.

Brands like Airbnb, Trident and Dunkin' Donuts have already successfully turned social-media content into television advertising by airing video commercials composed from user-generated Vine videos.

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Social-media sourcing. This is not to say that advertising departments will disappear or the role of professional marketers will evaporate. Marketers will continue to play a central role in how brands connect with consumers. But they will work more directly with consumers as they launch, manage and curate marketing campaigns that represent an increasingly unfiltered interaction with their customers.

Much of this unfiltered interaction is occurring via social media. But tapping photos, video and copy submitted through social media channels is a now versatile tool used for every facet of corporate marketing efforts. Indeed social media provides the content for email newsletters, marketing collateral, websites, in-store displays and television advertising.

Rapidly advancing technology puts user-generated content collection and management within the reach of almost all marketing departments. And an increasingly affordable suite of social-media management, analytics and A/B testing solutions allow brands to track, analyze and refine these efforts.

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Millennial word-of-mouth. Taxicabs will continue to roam city streets, and marketing departments will still spend big budgets on advertising creative work. But the 86 million members of the millennial generation will determine a new marketing direction fueled by the explosion of social- and mobile-powered commerce. Millennials account for $1.3 trillion consumer in spending, according to Barrons, and that number is expected to steadily grow.

Today, millennials’ spending is already largely dictated by consumer content. According to eMarketer, 68 percent of 18- to 34-year-old social media users were at least somewhat likely to make a purchase after seeing a friend's social media post.  

Millennials will soon not even think of hailing a cab when seeking to cross town. They will turn to their Uber or Lyft smartphone app out of habit and convenience. In the same way, the largest generation of consumers in U.S. history will soon not be swayed by prepackaged advertising directed by creative agencies. Instead they will seek out the photos, reviews and videos that show the consumer choices of their network of friends, acquaintances and fellow millennials.

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