Facebook is facing a backlash from users after replacing email addresses listed in members’ contacts with those provided by its @facebook.com system.
The company said it had acted to make details “consistent” across its site.
If Facebook’s email system takes off it could drive more traffic to the firm’s pages helping boost advertising sales.
But some users have branded the move “annoying” and “lame” and publicised instructions on how to display original addresses instead of the Facebook ones.
Emails sent to @facebook.com addresses appear alongside posts sent via the network’s internal message system, allowing users to pick up both types of communication from the same place.