I too received the email. The one thing in it that concerns me is this:
"If we do not hear from you by March 15, 2005, we will update your e-mail contact information so that you will not receive further e-mail communications from United."
Ok, United, how am I supposed to let you know that I want to continue receiving email without replying to this email to join MP???
And, yes, it came to the same email address as in my MP profile also...