Facebook Inc. (FB.O) unveiled a redesign that focuses on the Groups feature of its main social network, doubling down on a successful but controversial part of its namesake app — and another sign that Facebook is moving toward more private, intimate communication.

The changes, announced Tuesday at the annual F8 conference in San Jose, California, make Groups a bigger part of the Facebook user experience. A new design for the mobile app highlights the Groups that users have joined, and now shows a personalized feed of activity across all the groups people are part of in a special tab. The service long known as the "big blue app" is also getting a color change -- it will be framed in white instead of the company’s traditional hue.

The changes are Facebook’s biggest in five years, Chief Executive Officer Mark Zuckerberg said onstage at F8. The company has been pushing more aggressively into groups for the past two years as people shy away from posting things publicly and look for more intimate ways to connect with friends and family. Fast-growing meme and community groups have been a recent bright spot for Facebook amid a series of privacy scandals, and the company is also shifting its focus to deal with its own projections that people are spending less time on its namesake site.

“It has a much bigger focus on communities and making communities as central as friends," Zuckerberg said.

The CEO opened his remarks by reiterating Facebook’s plan to build a privacy-focused social platform. “We don’t have the strongest reputation on privacy right now," he said. “We need to change the way we’re running the company today."

Groups, which can be public or private on the social network, can be used to help keep long-distance friends in touch, connect people with similar interests or passions, and organize events. Facebook is also making it easier to discover new Groups based on users’ interests, and will recommend relevant groups to people when they are in other parts of the app, like Marketplace, the Gaming tab and its Watch video service. People will also be able to share content directly to their Groups from the share button on the main News Feed, the same way they do with friends and family, Facebook said.

The company is even rolling out specific features for different types of groups. For example, members in health-related groups can ask the group administrator to post on their behalf to better protect their privacy. Facebook is also adding more chat features for groups focused on gaming.

The growth of groups makes it more urgent for Facebook to reckon with the spammers, manipulators and hackers that exploit them to spread misinformation and conspiracy theories, among other things. In special counsel Robert Mueller’s indictment of 13 Russian nationals and three Russian entities for allegedly interfering in the 2016 U.S. election, several Facebook groups were cited as tools to support President Donald Trump’s campaign or oppose Hillary Clinton’s. More recently, Facebook groups have been blamed for amplifying anger and spreading misinformation during violent protests in France. On WhatsApp, an encrypted Facebook messaging service, private groups have been used to spread dangerous misinformation that has led to physical violence and even deaths.

In March, Zuckerberg said Facebook is undertaking a massive overhaul to focus on private, ephemeral and encrypted communication, recognizing that more people want to interact privately or in more intimate groups -- rather than the open-sharing model he built the company around. The company also aims to integrate Facebook’s different online properties, allowing users to send messages between WhatsApp, Instagram and Facebook Messenger.

Facebook will unveil a slew of other new features on Tuesday. The company’s Dating service is getting a new feature called Secret Crush that lets people "express interest in" up to nine of their Facebook friends. If one of these users has opted into Facebook Dating, they will get a notification saying someone has a crush on them. If that person adds the original admirer to their Secret Crush list, Facebook makes a match -- digitally, at least. Facebook Dating, which was announced at last year’s F8, is still free to users.

Menlo Park, California-based Facebook is also trying to facilitate non-romantic relationships. A “Meet New Friends” feature will make recommendations based on some shared connection — like living in the same city or working at the same company. It’s opt-in, so users will only see other people who are open to meeting new friends, and vice versa, the company said. It will also be integrated into Facebook Groups.

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The social network’s e-commerce service, called Marketplace, also got an upgrade. People who sell goods on Marketplace will soon be able to take payment directly through Facebook, including shipping costs, the company said. Today, people who sell goods have to arrange payment outside of Facebook, though they can do so via Facebook’s messaging app, Messenger.

PayPal Holdings Inc. will process payments for purchases made directly inside Marketplace, according to a company spokesperson. That’s the same payments partner Facebook’s Instagram is using to process in-app purchases. Facebook also says it is considering charging sellers a fee for facilitating these deals.

“We are evaluating a selling fee that is in line with competitive platforms to help cover payment processing and programs such as purchase protection,” a spokesperson said.