Threads, Meta’s rival to social media platform X, has launched in the European Union, months after being released elsewhere around the world.
The Instagram spin-off app went live in more than 100 countries in summer but not the bloc, after Meta officials delayed the social network's arrival in Europe citing “regulatory clarity” issues.
Meta has repeatedly come under the EU's regulatory microscope, particularly over concerns about how it uses people's data to serve highly targeted advertising.
More than 100 million people worldwide had joined Threads within a week of its summer introduction.
Meta chief executive Mark Zuckerberg used the platform itself to announce the European launch. "Today we're opening Threads to more countries in Europe. Welcome everyone," he wrote.
Meta said EU users can now create a Threads profile connected to their Instagram account but can also use the app without a profile to browse, share and even report content, as part of the company's compliance with EU rules.
They cannot, however, interact with Threads content nor post without an Instagram sign-on.
Instagram has about two billion users around the world.
Threads said it had added new features since its launch including a "following feed", the ability to edit a post, search with keywords and tag topics.
The EU has bolstered its legal armoury to rein in Big Tech, with stricter rules to protect European users online and boost competition in an industry dominated by US giants.
Under a landmark law known as the Digital Markets Act (DMA), the EU named Meta as a "gatekeeper" and its Facebook, Instagram and WhatsApp face tougher curbs.
The stricter rules especially affect the world's biggest online companies including Meta, Google Alphabet, Amazon Apple, TikTok parent ByteDance and Microsoft.
Mr Zuckerberg said a day earlier that Threads had begun tests where users' posts would also be available on similar text-based and open-source rival social networks such as Mastodon.
"Making Threads interoperable will give people more choice over how they interact and it will help content reach more people. I'm pretty optimistic about this," Mr Zuckerberg said in a Threads post.
Interoperability is also an EU goal. Under the DMA, the most popular messaging services will have to make it possible for users to send messages to other apps.
Meta is challenging the EU's designation of its instant messenger service Messenger as a "core platform service" and for its Facebook Marketplace also coming under the DMA's scope.
The company has struggled to comply with the strict rules of a 2018 EU data privacy regulation.
It hopes that by offering paid ad-free subscriptions in Europe for Facebook and Instagram for users unwilling to have their personal data harvested it will help to avoid further issues.
Threads chief Adam Mosseri also said this week that the app would extend its fact-checking programme next year.
"We currently match fact-check ratings from Facebook or Instagram to Threads, but our goal is for fact-checking partners to have the ability to review and rate misinformation on the app. More to come soon," he said on Threads.
Another milestone EU law is the Digital Services Act, which forces digital giants to aggressively police content online in the EU, including misinformation, disinformation and hate speech, against the risk of major fines.
The EU has passed increasingly stringent rules around how user data can be collected and used, forcing Big Tech companies like Meta to re-evaluate how they operate on the continent.
In October, Meta said it would give users in Europe an ad-free version of Facebook and Instragram in return for a subscription fee. The subscription services will be offered – alongside the free, ad-supported version – to anyone in the EU, Iceland, Liechtenstein, Norway and Switzerland.
