Facebook/Meta founder Mark Zuckerberg has a new Twitter clone that's more "friendly," but it seems the decision to design an app that looks exactly like Twitter is making Twitter suspicious that its intellectual property has been stolen.

Meta Chief Product Officer Chris Cox even called the Threads "our response to Twitter" apparently, meaning there's little ambiguity about the purpose and design of the app.

Twitter owner Elon Musk had thoughts:

Here was the cease-and-desist letter sent by Twitter to Meta on Thursday by lawyer Alex Spiro:

Dear Mr. Zuckerberg:

I write on behalf of X Corp., as successor in interest to Twitter, Inc. ("Twitter"). Based on recent reports regarding your recently launched "Threads" app, Twitter has serious concerns that Meta Platforms ("Meta*) has engaged in systematic, willful, and unlawful misappropriation of Twitter's trade secrets and other intellectual property.

Over the past year, Meta has hired dozens of former Twitter employees. Twitter knows that these employees previously worked at Twitter, that these employees had and continue to have access to Twitter's trade secrets and other highly confidential information; that these employees owe ongoing obligations to Twitter; and that many of these employees have improperly retained Twitter documents and electronic devices. With that knowledge, Meta deliberately assigned these employees to develop, in a matter of months, Meta's copycat "Threads" app with the specific intent that they use Twitter's trade secrets and other intellectual property in order to accelerate the development of Meta's competing app, in violation of both state and federal law as well as those employees' ongoing obligations to Twitter.

Responding to this specific allegation, Meta Communications Director Andy Stone denied that any former Twitter employees work on the engineering team over at Threads.

Twitter says it will "strictly enforce its intellectual property rights" and demanded the rival special media company "take immediate steps to stop using any Twitter trade secrets or other highly confidential information."

Please consider this letter a formal notice that Meta must preserve any documents that could be relevant to a dispute between Twitter, Meta, and/or former Twitter employees who now work for Meta.

That includes, but is not limited to, all documents related to the recruitment, hiring, and onboarding of these former Twitter employees, the development of Meta's competing Threads app, and any communications between these former Twitter employees and any agent, representative, or employee or Meta.

Tens of millions of people signed up for Threads on its first day.