[astura]

Send an email and see if that email shows up in your inbox?

[Gigablah]

If gmail ignores dots in the email address, of course that email is going to show up in your inbox.

[astura]

And if it shows up it someone else's inbox then you know that the other person registered a gmail account with the dots, which was the question.

[Gigablah]

Which goes back to my question; how did he know that there is another inbox? Unless he happens to know the other person... well, in person.

And if he knows them in person, why hasn't either of them switched email addresses already (within the last 10 years)? Something doesn't add up here.