Brief:

• Snapchat, the image-messaging app with 178 million users worldwide, is the most popular social media platform among U.S. teenagers, according to a study by RBC Capital. The bank found that 79% of 13- to 18-year-olds have a Snapchat account, compared to 73% for Instagram and 57% for Facebook.
• RBC asked respondents which app they would keep if they were "trapped on a deserted island" and could only pick one social network. Forty-four percent of teens chose Snapchat, compared to Instagram's 24% and Facebook's 14%. A year ago, 28% of U.S. teens said they would keep Snapchat.
• Messaging was the most important Snapchat feature among all ages, the survey found. Sixty-eight percent of Snapchat users ranked it No. 1, compared with 28% for Stories, the feature that lets users string together multiple videos and images, and 4% for Discover, the publishing platform for professional media companies.

Insight:

While Facebook is the most popular social network among age groups older than 18, Snapchat clearly holds sway among the up-and-coming Gen Z audience. The contrast among age groups is dramatic. Facebook, which has more than 2 billion users worldwide, was chosen by 64% of older participants to the "deserted island" question while its importance faded among the teenage cohort.

Snapchat clearly provides an advantage in reaching elusive, often ad-averse audiences like teens, which may portend stronger revenue growth for the embattled app as Gen Zers enter adulthood and accrue greater spending power. The popularity also speaks to young consumers' predilection toward messaging and visually-oriented messaging, in particular — areas marketers looking to engage these demographics should focus on. 

The survey confirms trends seen in other studies of Snapchat's popularity among teen cohorts. The photo-messaging app is the preferred social media platform for nearly half (47%) of teens, marking an increase of 12 percentage points year-over-year, Piper Jaffray found in an October survey. Only 24% of teens said Instagram was their favorite social media platform, marking a rise of 1 percentage point, while both Facebook and Twitter dropped in popularity to 9% and 7%, respectively.

Meanwhile, Facebook isn't standing still to watch its audience erode. The social network this month introduced Facebook Messenger Kids to appeal to youngsters, and its WhatsApp messaging platform and Instagram image-sharing app are hugely popular. Instagram's audience is forecast to grow 56% to 927.9 million users by 2021 from 593.7 million this year, researcher eMarketer estimated this month. Instagram is currently testing a standalone messaging app that would be the latest effort to undermine Snapchat by mimicking its features.