Facebook is trying to force its 900million users to switch to its own email service.
It is removing the personal email address displayed on an individual user's profile pages and replacing it with a @facebook.com address even if the member never uses it.
The social networking site's email service was launched two years ago but has failed to take off, possibly because most people do not like having multiple mail accounts.
Facebook users who were not consulted about the move responded with anger. Blogger Gervase Markham, one of the first to notice the change, said it was a form of computer hacking. 'What on earth do they think they are playing at?' he said.
On Twitter, Facebook was branded 'sneaky' while CNN technology expert Julianne Pepitone claimed it was an attempt to 'hijack your email address'.
But Anthony Mullen, an analyst at Forrester Research, said: 'This is a direction Facebook needs to move in. Facebook want to usurp existing email identities with their own to help drive up traffic to its site and lock users into its service.
The problem is the lack of transparency it has acted without asking for members' permission first.'
The US company is under pressure to lift its revenues following a stock market flotation. Because emails sent to the @facebook address will appear on the site's pages it will potentially boost page views and boost advertising sales. The email changes which apply only to users with the Timeline layout are an attempt to collapse a number of electronic methods of communication into one. If somebody sends a user an email it goes into the 'messages' folder on their Facebook page.
It is possible to turn off the email service.
A spokesman said: 'We are providing every user with his or her own Facebook email address because we find that many users find it useful to connect with each other, but using the Facebook email is completely up to you.'
- Daily Mail