Casey Johnston at Ars Technica has the details of what to me seems like a pretty sleazy move. I have definitely confirmed that the “About” part of my profile now shows the email at the FB domain instead of my actual email. Worse, as reported, there is no way for a user to change this, to remove the FB email or give preference to any other address over it. I have been on the fence about deleting my Facebook account for some time. This may be the final straw.
Facebook forces all users over to @facebook.com e-mail addresses, Ars Technica