It wasn't the username MattSayar, it's an alt account.
> I happen to have an account I post with that I don't generally want associated with my real name, so I figured it was a great test case
Interesting. I have a hard time believing that current models were actually able to place that connection by analyzing your writing style, unless both accounts were a part of the training set (they likely were), and the model was able to encode the similarities in the accounts during training.
The real world impact of this would be that new accounts that were not trained into the model would not be able to be deanonymized like this.
My point is that, if you created a new account and actively used it for a while, I don't think the current version of Grok (never trained on your new account) would ever be able to make that association. It's certainly interesting that it could do it, I just want to drill into the how.