While generally positive about the changes, Graham Cluley, a senior technology consultant at Sophos, said Facebook could go much further in protecting privacy by adopting a sweeping opt-in principle across its site.

To become "truly opt-in," Facebook should lock every setting to its most private and leave it up to each user whether they want to share their information more broadly, Cluley wrote in a .

Some have speculated that a key motivation for the changes is the recent launch of Google+. Google hoped its Circles privacy and sharing mechanism would be an attractive alternative to Facebook's controls, which have been criticized as too complex, causing people to expose content to a larger-than-intended audience.

"With several of these features, it's clear that Facebook is playing catch-up to Google+. Google showed that it was possible to build much better user interfaces, giving social network users more privacy with respect to some of their friends, family and co-workers, while sharing with others," said Peter Eckersley, technology projects director at the Electronic Frontier Foundation (EFF), via e-mail.

For now, Google+ is still in a limited beta trial and available only by invitation, so its estimated 25 million members are just a small fraction of the more than 750 million on Facebook. Ultimately, whether Facebook's announcement is a direct response to Google+ doesn't much matter, Consumer Watchdog's John Simpson wrote in a .