When Andrea Mallard started her new job as Pinterest's first chief marketing officer last November, she didn't know the company was heading for an initial public offering (IPO). Right after she joined, Mallard learned of the company's plans for a public listing, which happened six months later, and valued Pinterest at nearly $13 billion. "Obviously, that's a little bit of stepping on a rocket ship of activity and learning to get ready for it," Mallard said, speaking to CNBC at the Cannes Lions International Festival of Creativity in France on Tuesday. "As soon as we got through the mechanics of the IPO it was back to business as usual, in a wonderful way. So it was a really wonderful experience, it was really clarifying for me to understand where the company had come from and where it was going," she said. Mallard's focus remained on what was right for Pinterest, rather than the investor audience, she said. "Thinking about the impact on the markets is not ever the right first thing to think about, it's just doing the right thing for the business, period, is how I've always thought about it. And that ends up being the right thing for investors too. So yes, it's a new audience to contemplate but I don't think it actually changes my behavior," Mallard told CNBC.

A banner for the online image board Pinterest Inc. hangs from the New York Stock Exchange (NYSE) on the morning that Pinterest makes its initial public offering on April 18, 2019 in New York City. Spencer Platt | Getty Images News | Getty Images

Mallard joined Pinterest from Athleta, the women's sportswear brand owned by Gap. Co-founder Evan Sharp had seen an old video of her speaking at a conference in Spain and invited her for a chat. She went along, believing they would discuss Athleta's advertising, but several conversations later, she realized she wanted to work there. "I fell in love with the mission first, fell in love with the company and realized that that was the right place for me," she told CNBC. Her job is to create "an iconic global brand" by acquiring more people (known as "pinners") on to the platform. The number of people who use Pinterest on a monthly basis was up 22 percent in the first quarter to 291 million, it reported last month, and Mallard's focus is on getting more people outside its core U.S. market to sign up. Pinterest had around 35 staff at Cannes Lions this year and took over a section of the beach. Small meeting room cabanas stretched along a pier, while a "dreamers" area featured hammocks and printed streamers. Further along, British artist Yinka Ilori created an adults' playground, with a brightly-colored see-saw and roundabout, and in the corner there was a bar where guests could order custom cocktails. As with the other companies on the beach at Cannes (Facebook, Twitter, Google and Spotify all had large private areas on the sand), the aim was to do business and make new contacts, and Mallard also spoke on a panel organized by the Economist on Tuesday.

A woman browsing the Pinterest app. Rich Polk | Getty Images

Rather than have people spend a lot of time browsing ideas on Pinterest, Mallard said the platform is one that inspires people to do things in the real world, such as choose a color scheme for their home decor. "Brands should be additive and trying to add to the person's experience, so it's a net benefit — it's time well spent rather than distraction," she told the audience. Mallard doesn't think of the site as a social network, she said. People create inspiration boards on Pinterest that might inform future creative projects, rather than scrolling through other people's content, as they do on Facebook, for example. "(Pinterest is) an opportunity for you to focus on your own life, to invest in your own future and plan for it in a more deliberate exciting way. That's very different than perhaps watching someone else's past which is often what happens on social media," she told CNBC. It's also working on new ways for brands to advertise and earlier this month Ikea launched a shoppable catalog on the site. People answer a few questions to understand the home decor style they like and are then presented with a personalized catalog they can buy from.