Over the weekend Mark Zuckerberg's recently floated company began quietly displaying @Facebook email addresses on all of its users' Timelines.

The move immediately sparked anger from Facebookers, who complained that their third party email account names – such as Gmail or Hotmail – had been unceremoniously replaced without their say-so on the site.

It was hardly surprising to see the switch take place, however. Facebook for some time now has been working on building more communications into its network.

Way back in November 2010, Facebook began offering its users their own Facebook.com email addresses. But it's now applied those handles to its entire userbase.

The messaging system could mean that all users of the dominant social network may now be able to export the email addresses of their Facebook friends to third-party apps.

Google has long complained about Facebook's decision to shield this information from its competitors.

Mountain View's contacts API was kept open for third-party apps' makers on Facebook. That all changed when Google got cheesed off about Facebook's refusal to play nice with its data.

Google eventually prevented Facebook and other third-party apps from tapping its programming interface unless something similar was offered. Presumably, @Facebook.com could change all of that.

Ultimately, Facebook is also attempting to retain its users on the site for even longer by offering more and more communication options on its service.

The @Facebook handle can be hidden from a user's Timeline page, with the original third-party email address reinstated as the default address displayed to "friends" on the site. But Facebook's sneaky decision to replace those addresses with its own one demonstrates once again how little control it wants its users to have on the site.

After all, if it was in the business of transparency, the company would have notified everyone of the switch. ®