Polyvore today will let advertisers pay to place a trend in its mobile and desktop sites’ “trends” section, which highlights styles that consumers are viewing on the shopping-focused social network.

High-end fashion retailer LuisaViaRoma is the first brand to use the ad unit, promoting its new line “Luxe Bohemian.”

Promoted Trends should appeal to Polyvore users and brands and retailers, says Arnie Gullov-Singh, Polyvore’s chief revenue officer. Visitors to Polyvore use the social network to keep up on trends, and brands and retailers establish themselves as “styling authorities” to attract shoppers looking for those trends.

The new ad unit continues the evolution of Polyvore’s business model. Since its launch, the social network has let users curate products into a collage that the social network calls a “set.” Until 2013, it made money through an affiliate model, receiving a commission for each shopper who clicked from its site and bought on a retailer’s site. But it spent more than a year moving to a cost-per-click advertising model.

Since launching its Promoted Products ad unit, which lets an advertiser pay to promote a particular item, 300 advertisers have used the social network’s ads, which is about double the number that had advertised on Polyvore as of October, Gullov-Singh says. But while its advertiser base has grown, its user base has not; the social network says it has 20 million monthly unique users, which is roughly the same number it had in October.

To attract new users—and drive more consumers to move from “lurkers” who look at sets but don’t create their own—the social network earlier this month launched a second iPhone app called Remix.

The app highlights trending styles and offers users recommendations for items that might go with an item or trend.
While Polyvore plans to expand Promoted Trends to its mobile apps in the near future, at launch the ad unit is only visible to users on the social network’s desktop and mobile sites.