X has quietly begun training its Grok AI chat platform using members' public posts without first alerting anyone
https://help.x.com/en/using-x/about-grok
You have two options if you do not wish to allow X to use your posts to train Grok.
The first option is to make your account private
The better option, for most users, is to log into the X site from your desktop and click the More button at the bottom of your screen.
From there, click on Settings and privacy, select Grok under Data sharing and personalization, and then uncheck the "Allow your posts as well as your interactions, inputs, and results with Grok to be used for training and fine-tuning"
