2 million sign-ups in 2 hours: What to know about newly launched Threads

Meta, the parent company of Facebook, has officially launched Threads, a new "conversation" app that appears to be the firm's long-awaited counterpart to Twitter.

The app surpassed "2 million sign-ups in the first two hours," Mark Zuckerberg wrote on his Threads page.

Zuckerberg and Elon Musk averted a cage fight last month, but the companies they oversee -- Meta and Twitter, respectively -- are now squaring off in direct competition.

Zuckerberg's latest platform -- which launched Wednesday, a day earlier than anticipated -- offers a place "where communities come together to discuss everything from topics you care about today to what'll be trending tomorrow," an app store description said.

"Whatever it is you're interested in, you can follow and connect directly with your favorite creators and others who love the same things -- or build a loyal following of your own to share your ideas, opinions and creativity with the world," the app store description added.

Users, who must be at least 12 years old, are afforded the option to log into Threads through a preexisting Instagram account. For users under 16, (or under 18 in certain countries) their accounts will default to a private profile when they join Threads.

The platform allows users' posts to be up to 500 characters, including links, photos and videos running up to 5 minutes in length.

A privacy policy provided in the app store indicated that Threads may collect data from users related to a slew of categories: health and fitness, financial information, contact information, search history and purchases, among others.

Twitter, by comparison, collects information from users during use of the platform, when users provide the information directly and when Twitter receives data from third parties, the company's privacy policy says.

Responding sarcastically to news of the app, Musk criticized Meta in a tweet: "Thank goodness they're so sanely run," he said. The comment made reference to language reportedly used by Meta executives in a derisive description of Musk's performance atop Twitter.

Meta and Twitter did not immediately respond to a request for comment on the launch of the app.

The new app from Meta arrives days after Twitter weathered its latest in a string of difficulties under Musk, suffering an outage over the weekend across thousands of users in multiple countries, according to online tracking site DownDetector.

In turn, the platform imposed "temporary limits" on the number of posts users could view in a single day, Musk said on Saturday.

Musk, who runs Tesla and SpaceX, stepped down as CEO last month but retained a prominent role in the company as its executive chairman and chief technology officer.

In recent months, Twitter has appeared to take aim at services offered by Meta. In May, Twitter added encrypted messaging and announced plans to offer voice calls – both key features of Meta-owned WhatsApp.

The jockeying between the two companies escalated into apparent animosity between Musk and Zuckerberg last month.

In response to a post mentioning a Meta-owned counterpart to Twitter, Musk said in a tweet that he was willing to fight Zuckerberg in a "cage match."

On Instagram, Zuckerberg posted a screenshot of Musk's tweet and a caption: "Send Me Location."

The fight between the rival billionaires has not materialized. On Monday, however, Musk trained with Ultimate Fighting Championship fighter Georges St-Pierre, according to a tweet from St. Pierre that included a photo of Musk.

The launch of Threads also drew criticism from former Twitter CEO Jack Dorsey, who targeted the app's data collection policy. "All your Threads," Dorsey said. "Belong to us."

Dorsey previously criticized Musk's leadership at Twitter, saying in April that "all went south" at the platform after Musk's acquisition, CNBC reported.

Earlier this year, Dorsey launched his own alternative app: Bluesky Social. The platform remains invite-only as it undergoes testing. The company has not offered a timeline for when it plans to make the site public.

ABC News' Riley Hoffman contributed to this report.