San Francisco, California - Elon Musk's social media platform X, formerly known as Twitter, has expanded the data it gathers on users to include biometric information.

The kind of information being collected - and how it might be used - is getting attention from tech watchers.

"We may use the information we collect ... to help train our machine learning or artificial intelligence models for the purposes outlined in this policy," the company recently added to its online privacy policy

However, those exact purposes aren't entirely made clear - except being for authentication and the operation of services - and X's definition of biometric data is short on specifics. (The US Department of Homeland Security defines biometrics as "unique physical characteristics such as fingerprints, that can be used for automated recognition.")

X also plans to record information about its users' level of education and work history. That data, according to Musk's evolving company, will be used to provide job recommendations.

Changes to the platform's information gathering practices will take effect at the end of September.

Musk, who also owns car manufacturer Tesla and space exploration company SpaceX, announced in July the formation of his latest venture, xAI, "to understand reality "

However, weeks earlier, he and other leading tech pioneers signed an open letter calling for a pause in AI development until the technology could be better understood.

Musk posted a message on X Thursday, seemingly designed to assuage his customers' personal privacy concerns.

"Just public data, not DMs or anything private," he wrote.

Twitter also responded that "ID verification will be handled by a respected 3rd-party company instead of by X itself, and the data will only be stored for up to 30 days," raising more concerns and questions.