AT&T has joined the playing field of large corporations using blockchain, and filed for a blockchain-based patent intended to “map” social media histories, which many see as “controversial.” Although flaunting valuable uses, the system presents a variety of privacy concerns.

The patent titled “Blockchain-Based Social Media History Maps” describes a program with the ability to track career interests and discussions between platforms. According to CCN, the service would be much more useful in the hands of potential employers looking for their next hire.

But who will actually own the data AT&T collects? According to the application,

“instead of passing ownership of blocks or data between users, a social media account owner maintains primary ownership of his or her online transaction data.”

One thing to note is that the service will have access to a user’s shopping data, a powerful tool if placed in the hands of marketers.

If awarded the patent, it’ll be interesting to see how AT&T utilizes it, and how its blockchain elements function.