Facebook is slurping mobile phone numbers from its users without explaining why, it has emerged.

In an upcoming overhaul to the social network's data use policy, Facebook said it had made a number of updates about the information it receives about individuals using the free content ad network.

It includes simplifying the language it uses to explain what information it receives from users whenever they are using or "running" Facebook. It said it was also clarifying that some of that information reveals details about the device itself such as an IP address, operating system or – surprisingly – a mobile phone number.

The Register has asked Facebook to clarify this point as it's not clear from the revised policy wording if a mobile number is scooped up without an individual's knowledge or as a result of it being previously submitted by that person to access some of the company's services. Importantly, Facebookers are not required to cough up their mobile phone number upon registering with the service. At time of writing, Facebook was yet to respond with comment.

The Nasdaq-listed company announced yesterday that it once again planned to rejigger its user policies, in part in response to a $20m US legal settlement.

Facebook has agreed to explain how it uses a name, profile picture, content and information in connection with ads after it got into hot water over its Sponsored Stories function, which – without prior consent – served adverts to Facebookers featuring the faces and names of people who had "Liked" a particular product.

The Mark Zuckerberg-run outfit now states that it will no longer take responsibility for how those ads are served, because users will have agreed to that usage upon signing up to the network. Existing users will also be expected to simply comply with the new terms, or else ditch Facebook in protest against how their data is being re-purposed:

Our goal is to deliver advertising and other commercial or sponsored content that is valuable to our users and advertisers. In order to help us do that, you agree to the following: You give us permission to use your name, profile picture, content, and information in connection with commercial, sponsored, or related content (such as a brand you like) served or enhanced by us. This means, for example, that you permit a business or other entity to pay us to display your name and/or profile picture with your content or information, without any compensation to you. If you have selected a specific audience for your content or information, we will respect your choice when we use it. If you are under the age of eighteen (18), or under any other applicable age of majority, you represent that at least one of your parents or legal guardians has also agreed to the terms of this section (and the use of your name, profile picture, content, and information) on your behalf. We do not give your content or information to advertisers without your consent. You understand that we may not always identify paid services and communications as such.

Facebook also made it clear that the company can use photo recognition software to correctly identify people on the network. It said:

We are able to suggest that your friend tag you in a picture by scanning and comparing your friend's pictures to information we've put together from your profile pictures and the other photos in which you've been tagged.

Facebook added that individuals can control that tagging function by finding the adequate setting (in this case: "Timeline and Tagging") to turn photo recognition off.

It is also having to tell people that when they're casually browsing the free content ad network on mobile devices, they are paying operators for any data they use "including sponsored or commercial content".

And, for the few among us who still believe the conceit that Facebook is first and foremost about connecting people across the globe, the company stated that there were "special provisions applicable to users outside the United States".

It continued:

We made [it] clear that you are not allowed to use Facebook if you are prohibited from receiving products or services from the United States.

The network is, of course, jammed with ads. So presumably a country such as Cuba, for example, will no longer be granted access to Facebook given that the US has maintained an economic embargo against the South American country since 1960.

After all, Facebook can't make ad bucks from Cubans who cannot access goods and services offered by US corporations.

The policy changes will be applied by the end of next week and come less than a year since Facebook last tweaked its "privacy" settings. ®