Facebook might be America’s favorite mobile app, but it’s willing to share the love.

The social media giant on Monday launched a new feature that helps advertisers promote an app — getting advertisers in front of the users who are most likely to “take action” within an app. In the case of retailers, this means they will be able to better target the shoppers who are more apt to buy from an app.

The feature, App Event Optimization, uses historical data garnered from the millions of Facebook and Instagram users to determine who is most likely to “take actions.” Facebook said mobile commerce and gaming apps found success while testing the feature.

Poshmark marketing manager Michelle Lo said Facebook helped the resale platform find users who were most likely to make a purchase in the app, which cut its cost per event by 24 percent.

App Event Optimization is now available worldwide. And in the next few weeks, Facebook will be expanding its dynamic ads and Canvas ads to those who are looking to drive app installs and app engagement.

In the world of mobile, having an app — or getting a customer to download an app — is often just the beginning. Research from Forrester has shown most smartphone users only spend time in about five apps. Facebook topped the list with Google close behind.

Although mobile commerce is on the rise, there is a marked distinction between browsing and researching on one hand and actual purchases on the other. Forrester suggests mobile discovery and browsing does not convert into mobile sales. Although one-third of retailer Web traffic is from phones, only 11 percent of sales come from mobile.

But apps, as opposed to the mobile browser experience, are the leaders in mobile commerce. Forrester estimates 85 percent of time spent on a mobile device is within apps, and eMarketer found that 58 percent of mobile purchases in the U.S. are made in apps.

This is part of the disconnect Facebook is trying to address.

In the case of one of Facebook’s dynamic ads, if a person indicated an interest in a product on a website, they will be shown an app install ad that includes that product. A Canvas ad is considered more “immersive,” in that it gives users a look at what they might expect within the app being advertised.

Chief operating officer Sheryl Sandberg said in April that more than three million businesses use Facebook advertising products, while more than 200,000 businesses advertise on Instagram, every month. Sandberg also noted that 82 percent of its advertising revenues came from mobile ads.