[dcurtis]

I updated the post to reflect reality.

Usually, Posterous catches this stuff and sends an email asking you to confirm that you really are you. They analyze the headers more closely than just looking at the name. For some reason, this didn't work in this case.

[coderdude]

According to him he just changed his email address to your email address in Outlook.

Edit: dcurtis edited his comment. Originally he claimed there was some kind of secret algorithm that prevents spoofing.

[loup-vaillant]

But, if they only analyse the headers, they are screwed anyway. Don't they also check the IP of the SMTP server as well or something?