• Meta's new Twitter competitor Threads has exploded in growth in its first full day since its public debut Wednesday night, fueled by Instagram's already massive userbase.
• The text-based social media product already has more than 50 million signups, according to screenshots some users have posted of their joining information.
• "Meta only needs 1 in 4 Instagram users to use Threads monthly for it to be as big as Twitter," Insider Intelligence Principal Analyst Jasmine Enberg said in a statement.

Meta's new Twitter competitor Threads has exploded in growth in its first full day since its public debut Wednesday night, fueled by Instagram's already massive userbase.

The text-based social media platform already has more than 50 million signups, according to screenshots some users have posted of their joining information. As of Thursday afternoon, The Verge reported that users had already posted more than 95 million posts and 190 million likes, based on internal company data it had viewed. Meta did not immediately respond to CNBC's request on Friday morning to confirm its latest metrics.

The booming growth is helped along by the fact that Threads is tied to an existing social network, Meta's Instagram. Users can sign up with their existing handles on Instagram and are able to retain some of their following as others sign up for the app.

"Meta only needs 1 in 4 Instagram users to use Threads monthly for it to be as big as Twitter," Insider Intelligence Principal Analyst Jasmine Enberg said in a statement. Twitter reported nearly 238 million monetizable daily active users in its last quarterly earnings report as public company last summer.

The app still has plenty of room to grow, having not yet launched in Europe, where Instagram's chief said there is still some regulatory complexity to navigate.

Twitter owner Elon Musk appears to have already shown some concern about Threads, as his longtime lawyer Alex Spiro wrote a letter to Meta accusing the company of "unlawful misappropriation" of trade secrets.

"No one on the Threads engineering team is a former Twitter employee," Meta's communications director Andy Stone wrote on Threads in response to the letter. "That's just not a thing."

Still, growth alone won't be enough to make Threads an alternative to Twitter that withstands the test of time. The app must also show that it can keep users engaged and coming back.

While Twitter is known for being heavily used by journalists, politicians and academics and is a place where news often breaks, Meta's Threads could have a much broader audience and focus due to its tie-in to Instagram, which has different use cases as a visual-based platform. Plus, Meta has taken steps to de-emphasize political content on Facebook, a policy which, if carried over to Threads, would set it apart from Twitter.

"News hounds and avid Twitter loyalists aren't likely to defect to Twitter, and Meta will need to keep Threads interesting to maintain the momentum once the novelty wears off," Enberg wrote. "It's also not a given that people will use Threads to keep up with news and world events like they do on Twitter, and the culture will be different. But that could work in Meta's benefit: Even the most engaged Twitter users are fed up with the constant chaos and ad hoc changes, and Threads could offer a nice reprieve."

Even so, many politicians have already signed up for the service. Axios reported that as of Thursday evening, more than a quarter of Congress' 535 members across both chambers had created accounts, as well as half a dozen Republican presidential candidates and top White House aides.

Many advertisers who are used to working with Meta are also likely to welcome an alternative to Twitter, especially if they view it as more brand-safe. The company has said Instagram's community guidelines will also apply to Threads.

WATCH: Meta's Threads is not Twitter killer, but will pose real threat to Twitter's growth: Analyst