[RasputinsBro]

> That proves the person logged into the account is authorised to log in, not that the owner of the account is a particular person or the same person that owns another account on another service.

Keybase can't know who the person logged into the account is either. But they can tweet, and so keybase will tell everyone that the twitter account which has signed tweets using my private keep is tweeting.

[robjan]

> Keybase can't know who the person logged into the account is either. But they can tweet, and so keybase will tell everyone that the twitter account which has signed tweets using my private keep is tweeting.

This is true. In the scenario where the account is compromised you are supposed to revoke the signature.