Facebook, the world’s most popular social-networking platform, has expanded its facial recognition technology to countries outside of the United States.

The "Tag Suggestions" feature makes use of the facial recognition technology that automatically scans all photos posted on Facebook and suggests the names of the members who appear in the frame to accelerate the process of making acquaintances.

The new feature has raised many eyebrows as privacy advocates fear that the feature could expose users to privacy threats.

Sophos, Internet security consultant firm, used its official blog to claim that a number of Facebook users were complaining that the site enabled the facial recognition feature without notifying them.

Senior technology consultant Graham Cluley from Sophos said, “Yet again, it feels like Facebook is eroding the online privacy of its users by stealth.”

Any Facebook member who does not want to be tagged automatically will have to opt out as the default setting of the new feature comes opt in.