Facebook cannot guarantee privacy: Why is the 'social inbox' so different?

Facebook's announcement today is "not designed [to be] an email killer", as described by CEO Mark Zuckerberg earlier this morning.

It's not email as such; it's more of a way to expand the existing messaging system and to consolidate your communications on the social network. Facebook is not becoming an email server in that all your existing Gmail or Hotmail goes through the site, though.

It does add more lines of communication in and out of the site, in form of your own dedicated @facebook.com email address - your existing username, to allow greater freedom whilst amalgamating the existing chat and SMS messaging all into one place.

Whoop-de-doo.

But as more people will be tempted by the new inbox feature that has just been announced, the more data Facebook has of you where otherwise they might not have. And with this comes even higher risk that your consolidated social lives are at further risk from the counter-privacy brigade.

Gallery To see the updated Messages unified inbox, including screenshots of how to get it working and how it operates, head on over to the gallery.

The higher they get, the harder they fall. And if Facebook were to fall, so would every one of its 500 million-plus users.

Instead of going out on a rant as I normally do about privacy and Facebook, and slamming them together to create the anti-Christ of the web, I won't bother. It's something I have covered far too many times before, as too has every other technology journalist on the planet. So by all means read some previous evidence of Facebook's misdemeanour's:

• Facebook does not erase user-deleted content
• The vigilante's guide to social networking
• Google Apps and Facebook's recent inbox controversies
• Facebook 'hijack any live chat' serious bug forces downtime
• Facebook privacy settings 'better'; doesn't undo the damage already done

Now they are branching out to email, essentially; in that you will be able to send email to another Facebook user and it appears within the site, and receive email from another Facebook user.

An argument between what is more personal for the user ranges on: the email inbox or the social network? Ultimately it doesn't matter, because regardless of either of these being breached is the possibility that some varying degree of breach will cause you to suffer either personally or professionally.

I, for one will not be using Facebook's new consolidated system where possible, and will be disabling it as soon as I am able to. Because of the large amount of personal data that I inadvertently submitted to Facebook over the years, starting back in 2006 before I started to write here, I am already in too deep. I put this down to, what my colleague Ed Bott describes as "youthful folly".

But once I realised the breadth of the potential for information abuse, I restricted the latest and greatest features which many ranted and raved about. All it now takes is one breach of my password and I am ripped open to the potential for huge abuse.

Update: The Guardian has a few thoughts for how the new Messages application could be used for cybercriminals. It offers a few scenarios which are not impossible which could allow abuse and spam to filter through. However there are some good bits to take into account also, but I suspect real-world trailing and testing will weed out the worst problems.

This will be no different, and I shall keep my social network limited internally as much as I can, regardless of how amazing this feature may or may not turn out to be.

Will you be using this new email inbox? Are you concerned about Facebook's privacy management and track record? Have your say.