Can Facebook have your number?

New Facebook security feature makes it safer to use public computers, but mobile number is required

Repeatedly made apparent in the news, based on both a Skype partnership rumor and statements made by CEO Mark Zuckerberg, Facebook is serious about bulking up its mobile presence. Though he’s not necessarily concentrating all his efforts on the mobile space, Zuckerberg has acknowledged that mobile will play a major role in manifesting Facebook’s goal of becoming a ubiquitous social Web platform.

“[M]aybe we’ll build specific apps for iPhone and Android,” said Zuckerberg in an interview, explaining the early stages of Facebook’s mobile strategy. “And then, for something that is as important as iPhone or Android, we’ll also build integration into the operating system. So for iPhone, we built in contact syncing, and for Android we integrated and did contact syncing pretty seamlessly. The question is – what could we do if we also started hacking at a deeper level, and that is a lot of the stuff that we’re thinking about.”

To acquire the deep-level access Facebook’s developers really want, the social network must prove that it has something really irresistible to offer users. Like, say, a flawless address book that always stays up to date.

Such an ideal offering seems like it could be at least part of the internal motivation behind Facebook’s Tuesday afternoon announcement of a new tool called “one-time passwords.”

Instead of having to worry about whether you signed out of Facebook from that public computer or whether the browser stored your password on the computer, you can just sign in with a password that only lasts temporarily. You simply text “otp” (for “one-time password”) to 32665, and the reply contains a new password that expires in 20 minutes.

The key is that users must have their mobile phone number listed in their account to take advantage of one-time passwords.

Undoubtedly, this is a really clever way to make checking Facebook from a public computer much more secure. Wouldn’t it be even more clever if this were just subtle encouragement for all Facebook users to update their account with a mobile phone number?

Along with one-time passwords, Facebook also launched two other new security features. Now everyone can sign out of the site remotely from other devices (computers or phones) via Account Settings. Finally, Facebook will regularly prompt users on login to verify security information, in case account access is ever lost.

One-time passwords will be rolling out to users over the next few weeks.