But in a twist to the tried-and-true contest formula, Nordstrom conducted the event on Snapchat, the social media platform popular with young adults and teenagers that lets people share images or video clips with friends for brief moments.

Nordstrom pitted the University of South Carolina, University of Oregon, University of Arizona, UCLA, and Florida State University against each other, challenging each school to “snap” a screenshot of their school’s name, with the college garnering the most crowd-sourced votes winning the prize: the party, hosted by prominent fashion model and coder Karlie Kloss, and $100 vouchers each for 2,000 seniors to be used to buy shoes for their job search.

The retailer says the resulting Snapchat video was viewed more than 6.7 million times and the filter was used more than 234,000 times, giving the retailer the kind of exposure to millennials it needs to replenish its customer base. (USC won, by the way.) It also boosted Nordstrom’s Snapchat following by 60%.

“It’s a great storytelling platform. We wanted to be really engaging and enable them to participate in our brand,” says Bryan Galipeau, Nordstrom’s director of social media. “One of our key principles in social media is how to be authentic and engage with our customers in a way they use the platform naturally.”

Nordstrom—which gets 21% of its business online, a very high percentage for a traditional retailer—has spent hundreds of millions of dollars over the last few years on things like distribution centers and inventory management software to integrate stores with its digital operations. A lot of that heavy lifting has been completed, and the retailer is now looking to take better advantage of social media.

Snapchat, launched in 2011, fit the bill. It has some 100 million daily users, and it is designed to share temporary content; anything “snapped” has an expiration date. Images and videos are removed from Snapchat’s servers once someone views the message, and they are given only a short time to do so.

The Seattle-based department store chain only got active on Snapchat in November, but its popularity with the next generation of shoppers that Nordstrom wants to cultivate proved irresistible. By some estimates, some 60% of people aged 13 to 34 are on the platform. That’s crucial given department stores’ declining popularity with so-called millennials, or shoppers between 18 and 34.

Nordstrom is also active on other social media platforms: the retailer has 1.8 million followers on Instagram, 3.9 million “likers” on Facebook (FB), and 688,000 followers on Twitter (TWTR).

Twitter allows Nordstrom to send news to shoppers, and Instagram showcases images of its fashions. Facebook hosts discussions, and Pinterest opens the door for some shopping. But Snapchat lets Nordstrom’s shoppers interact with each other and have a role in producing the content.

Nordstrom has recently hit a bumpy patch. Though online sales soared by 11% during the holiday quarter, comparable sales fell 3.2% at its namesake department stores, dropping for the second quarter in a row. Meanwhile at the Rack, its chain of discount stores, comparable sales fell 3%.

Nordstrom is hardly the only retailer to embrace Snapchat: Last summer, Target (TGT) pushed college textbook images through the platform on 50 college campuses as part of an ongoing back-to-school campaign. H&M and Sephora have also done big marketing efforts with the platform.

Nordstrom moved carefully so the effort didn’t come across as a blatant commercial for the company. “It’s a fun way to interact and not directly tied to selling shoes. It’s really about creating a unique experience associated with Nordstrom,” Galipeau said.