[niftich]

The quote from the article is the writer jumping through some creative contortion to try to explain keybase prove [1] feature to a layperson.

The idea is to prove control of some social identity; then correspondingly, others on Keybase will have increasing confidence that the person in question who has proven a few third-party accounts is indeed the same person. This doesn't mean that that person is actually-actually George Washington (which is a much more difficult problem to solve), just that the person who purports to be George Washington on Keybase does indeed control some accounts on Facebook, Twitter, etc, so if you would have vested some trust into their Facebook identity, you can vest at least equivalent trust into their corresponding Keybase identity.

[1] https://keybase.io/docs/command_line