The bug appears to have resulted from a change the site made that was designed to encourage users to employ their Facebook e-mail addresses more often. During the change, all members' @Facebook.com addresses became the only one shown on the user profiles.

'Consistent Across the Site'

Facebook told news media via e-mail that the change was implemented to update addresses and "make them consistent across the site." It said that, in addition to everyone receiving a Facebook.com address, the site was also "rolling out a new setting that gives people the choice to decide which addresses they want to show on their timelines."

The site said that users have had the ability to control which posts to show or hide on the timeline, and now it was "extending that to other information they post, starting with their Facebook address."

At first, Facebook indicated that making the @facebook.com address the default visible one was intentional so that everyone would have the same status, since it could be changed by the user. The idea was apparently that the @facebook.com address is the same as the information in a user's profile URL, meaning that it's already available to other people. The site decided to hide everyone's personal e-mail address, unless the user decided to make it public.

The update apparently affected at least some smartphones' contacts and address book listings, if the smartphones were set for syncing contacts between those devices and the Facebook accounts. This would mean that e-mails from those devices have been going to those contacts' Facebook addresses, assuming the contacts were on Facebook.

Updating Your Info

Some users are reporting, however, that e-mails sent to those Facebook addresses do not actually appear in the Facebook e-mail boxes, but have gotten lost somewhere.

A Facebook spokesperson told news media that, for some devices, "a bug meant that the device was pulling the last e-mail address added to the account rather than the primary e-mail address," which apparently resulted in the @facebook.com addresses being pulled.

Some Facebook observers have noted that the bug fix likely will not resolve the fact that the visible e-mail address now shows @facebook.com. To fix that, users will need to Update Info on the Timeline or on the About page, and edit the Contact Info box. In Contact Info, the user will need to select which e-mail address to show on the Timeline, as the original e-mail address should still be listed.

Since anyone who knows your user name can now deluge you with e-mail at your Facebook account, a user can change that by going to the Privacy Settings in the top right of a Facebook page. Under How to Connect, select Edit Settings and then select who can send you messages.