Facebook to start asking all users to verify their phone numbers
In true Facebook fashion, they are trying to get every possible bit of information from their 900+ million users. The next step will be a new message that will sit atop your news feed. Some are already seeing it. The new message will ask you to “stay in control of your account” and send you over to the Facebook Security page - where you can verify your mobile number with the social giant.
As though the information that Facebook ALREADY has about users is insufficient, now they want this as well!
Facebook has offered the means to include phone number, as well as mother and father’s names, birth dates, all sorts of stuff, in one’s profile, should users want. But Facebook never requested it explicitly. It was merely a field that you could choose to fill in or leave blank and forget about.
Why now, Facebook?
I wonder what Facebook’s motive is, in choosing to push users for this information.

Well, from David’s post, the request is for mobile phone numbers only.
Ahh, okay, that answers my question!
It is part of the Facebook mobile strategic plan. This might involve a mobile phone O/S, and certainly included purchase of Instagram and even more recently Pieceable, a mobile app testing platform.
(Source: bitshare)
In true Facebook fashion, they are trying to get every possible bit of information from their 900+ million users. The next step will be a new message that will sit atop your news feed. Some are already seeing it. The new message will ask you to “stay in control of your account” and send you over to the 
